Heterocyclic compound and organic light-emitting device including the same

ABSTRACT

An organic light-emitting device includes: a first electrode; a second electrode facing the first electrode; and an organic layer between the first electrode and the second electrode, the organic layer comprising an emission layer comprising the heterocyclic compound of Formula 1 as a host or as a delayed fluorescent dopant. The organic light-emitting device including the heterocyclic compound may have a low driving voltage and excellent maximum quantum efficiency:

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2017-0024249, filed on Feb. 23, 2017, in the KoreanIntellectual Property Office, the entire content of which isincorporated herein by reference.

BACKGROUND 1. Field

One or more aspects of one or more embodiments of the present disclosureare directed toward a heterocyclic compound and an organiclight-emitting device including the same.

2. Description of the Related Art

Organic light-emitting devices are self-emission devices that producefull-color images, and also have wide viewing angles, high contrastratios, short response times, and excellent characteristics in terms ofbrightness, driving voltage, and response speed, compared to devices inthe art.

The organic light-emitting device may include a first electrode disposed(e.g., positioned) on a substrate, and a hole transport region, anemission layer, an electron transport region, and a second electrode,which are sequentially disposed on the first electrode. Holes providedfrom the first electrode may move toward the emission layer through thehole transport region, and electrons provided from the second electrodemay move toward the emission layer through the electron transportregion. Carriers, such as holes and electrons, may then recombine in theemission layer to produce excitons. These excitons transition from anexcited state to a ground state, thereby generating light.

SUMMARY

One or more aspects of one or more embodiments of the present disclosureare directed toward a novel heterocyclic compound and an organiclight-emitting device including the same.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

An embodiment of the present disclosure provides a heterocyclic compoundrepresented by Formula 1 below:

In Formulae 1 and 2,

X₁ to X₈ may each independently be selected from N, CR₂, and CAr₁,provided that at least one of X₁ to X₈ is CAr₁,

X₁₁ to X₁₈ may each independently be N or CR₃,

Y₁ and Y₂ may each independently be selected from a single bond, O, S,NR₁₁, CR₁₂R₁₃, SiR₁₄R₁₅, CO, SO, SO₂, and POR₁₆,

when one of X₁ to X₈ is CAr₁ and Y₁ is a single bond, Y₂ may be selectedfrom O, S, CR₁₂R₁₃, SiR₁₄R₁₅, CO, SO, SO₂, and POR₁₆,

Ar₁ may be represented by Formula 2,

L₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group or asubstituted or unsubstituted C₁-C₆₀ heterocyclic group,

R₁ to R₃ may each independently be selected from hydrogen, deuterium,—F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group,—Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a substituted or unsubstitutedC₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group,a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted orunsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted monovalentnon-aromatic condensed heteropolycyclic group,

two or more neighboring R₂(s) may optionally be linked to form asubstituted or unsubstituted ring,

two or more neighboring R₃(s) may optionally be linked to form asubstituted or unsubstituted ring,

R₄ may be selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylgroup, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, and asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group,

R₁₁ to R₁₆ may each independently be selected from hydrogen, deuterium,—F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group,—Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a substituted or unsubstitutedC₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group,a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted orunsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted monovalentnon-aromatic condensed heteropolycyclic group, and neighboringsubstituents may optionally be linked to form a substituted orunsubstituted ring,

a1 may be an integer from 0 to 5,

b1 may be an integer from 1 to 5,

at least one substituent of the substituted C₅-C₆₀ carbocyclic group,the substituted C₁-C₆₀ heterocyclic group, the substituted C₁-C₆₀ alkylgroup, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substitutedC₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group,the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, thesubstituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group,the substituted C₁-C₆₀ heteroaryl group, the substituted monovalentnon-aromatic condensed polycyclic group, and the substituted monovalentnon-aromatic condensed heteropolycyclic group may be selected from:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and aC₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group, a biphenylgroup, and a terphenyl group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group, a biphenylgroup, and a terphenyl group, each substituted with at least oneselected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amidino group, a hydrazino group, a hydrazonogroup, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, a biphenyl group, and a terphenylgroup; and

—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

Q₃₁ to Q₃₃ may each independently be selected from hydrogen, deuterium,—F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, anamidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀ alkylgroup, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxygroup, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, aC₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀aryl group, a C₆-C₆₀ aryl group substituted with a C₁-C₆₀ alkyl group, aC₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclicgroup, a monovalent non-aromatic condensed heteropolycyclic group, abiphenyl group, and a terphenyl group, and

* indicates a binding site to a neighboring atom.

Another embodiment of the present disclosure provides an organiclight-emitting device including: a first electrode; a second electrode;and an organic layer between the first electrode and the secondelectrode, the organic layer including an emission layer, wherein theorganic layer includes the heterocyclic compound.

BRIEF DESCRIPTION OF THE DRAWING

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the FIGURE which is a schematic view of an organiclight-emitting device according to an embodiment.

DETAILED DESCRIPTION

Reference will now be made in more detail to embodiments, examples ofwhich are illustrated in the accompanying drawings, wherein likereference numerals refer to like elements throughout. In this regard,the present embodiments may have different forms and should not beconstrued as being limited to the descriptions set forth herein.Accordingly, the embodiments are merely described below, by referring tothe FIGURES, to explain aspects of the present description. As usedherein, the term “and/or” includes any and all combinations of one ormore of the associated listed items. Expressions such as “at least oneof,” “one of,” and “selected from,” when preceding a list of elements,modify the entire list of elements and do not modify the individualelements of the list. Further, the use of “may” when describingembodiments of the present invention may refer to “one or moreembodiments of the present invention.”

A heterocyclic compound according to an embodiment is represented byFormula 1 below:

In one embodiment, X₁ to X₈ may each independently be selected from N,CR₂, and CAr₁, and at least one of X₁ to X₈ may be CAr₁.

In one embodiment, one of X₁ to X₈ may be N and the others thereof mayeach independently be CR₂ or CAr₁; or X₁ to X₈ may each independently beCR₂ or CAr₁.

In one embodiment, X₃ or X₆ may be CAr₁.

In one embodiment, X₁₁ to X₁₈ may each independently be N or CR₃.

In one embodiment, Y₁ and Y₂ may each independently be selected from asingle bond, O, S, NR₁₁, CR₁₂R₁₃, SiR₁₄R₁₅, CO, SO, SO₂, and POR_(m),and when one of X₁ to X₈ is CAr₁ and Y₁ is a single bond, Y₂ may beselected from O, S, CR₁₂R₁₃, SiR₁₄R₁₅, CO, SO, SO₂, and POR₁₆.

In one embodiment, Y₁ may be selected from O, S, NR₁₁, CR₁₂R₁₃,SiR₁₄R₁₅, CO, SO, SO₂, and POR_(m), and Y₂ may be selected from a singlebond, O, S, NR₁₁, CR₁₂R₁₃, SiR₁₄R₁₅, CO, SO, SO₂, and POR₁₆; or Y₁ maybe a single bond, and Y₂ may be selected from O, S, CR₁₂R₁₃, SiR₁₄R₁₅,CO, SO, SO₂, and POR₁₆.

In one embodiment, Formula 1 may be selected from Formulae 1-1 to 1-10:

In one embodiment, Ar₁ may be represented by Formula 2.

In one embodiment, Ar₂ in Formulae 1-9 and 1-10 may be the same asdescribed in connection with Ar₁.

In one embodiment, Formula 2 may be selected from Formulae 2-1 to 2-19:

Formulae 2-1 to 2-19 may be substituted or unsubstituted with one ormore R₃(s) (e.g., at any of the X₁₁ to X₁₈ positions in Formula 2), andwhen Formulae 2-1 to 2-19 are substituted with two or more R₃(s), theR₃(s) may be identical to or different from each other.

In one embodiment, L₁ may be a substituted or unsubstituted C₅-C₆₀carbocyclic group or a substituted or unsubstituted C₁-C₆₀ heterocyclicgroup.

In one embodiment, L₁ may be selected from:

a benzene group, a naphthalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a naphthofluorene group,a pyridine group, a pyrimidine group, a pyridazine group, a triazinegroup, a pyrrole group, a thiophene group, a furan group, an imidazolegroup, a pyrazole group, an oxazole group, an isoxazole group, athiazole group, an isoxazole group, a triazole group, a carbazole group,a dibenzofuran group, a benzonaphthofuran group, a dibenzothiophenegroup, a benzocarbazole group, and a dibenzocarbazole group; and

a benzene group, a naphthalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a naphthofluorene group,a pyridine group, a pyrimidine group, a pyridazine group, a triazinegroup, a pyrrole group, a thiophene group, a furan group, an imidazolegroup, a pyrazole group, an oxazole group, an isoxazole group, athiazole group, an isoxazole group, a triazole group, a carbazole group,a dibenzofuran group, a benzonaphthofuran group, a dibenzothiophenegroup, a benzocarbazole group, and a dibenzocarbazole group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a methyl group, an ethyl group, apropyl group, an isobutyl group, a sec-butyl group, a ter-butyl group, apentyl group, an iso-amyl group, a hexyl group, a C₁-C₂₀ alkoxy group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopentenyl group, a cyclohexenyl group, a phenyl group, a naphthylgroup, a fluorenyl group, a carbazolyl group, a dibenzofuranyl group, abenzonaphthofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, and a dibenzocarbazolyl group.

In one embodiment, R₁ to R₃ may each independently be selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, —Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a substituted orunsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, asubstituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, and a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group,where neighboring R₂(s) may optionally be linked to form a substitutedor unsubstituted ring, and neighboring R₃(s) may optionally be linked toform a substituted or unsubstituted ring, and

R₁₁ to R₁₆ may each independently be selected from hydrogen, deuterium,—F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group,—Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a substituted or unsubstitutedC₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group,a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted orunsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted monovalentnon-aromatic condensed heteropolycyclic group, where neighboringsubstituents may optionally be linked to form a substituted orunsubstituted ring.

In one embodiment, R₁ to R₃ may each independently be selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, —Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a substituted orunsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, anda substituted or unsubstituted C₁-C₆₀ alkoxy group.

In one embodiment, R₁ to R₃ may each independently be selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, —Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a methyl group, anethyl group, a propyl group, an isobutyl group, a sec-butyl group, ater-butyl group, a pentyl group, an iso-amyl group, a hexyl group, and aC₁-C₂₀ alkoxy group; and

—Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a methyl group, an ethyl group, apropyl group, an isobutyl group, a sec-butyl group, a ter-butyl group, apentyl group, an iso-amyl group, and a hexyl group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a methyl group, an ethyl group, a propylgroup, an isobutyl group, a sec-butyl group, a ter-butyl group, a pentylgroup, an iso-amyl group, and a hexyl group, and

Q₃₁ to Q₃₃ may each independently be selected from hydrogen, deuterium,—F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, anamidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀ alkylgroup, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, aC₆-C₆₀ aryl group, a C₆-C₆₀ aryl group substituted with a C₁-C₆₀ alkylgroup, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensedpolycyclic group, a monovalent non-aromatic condensed heteropolycyclicgroup, a biphenyl group, and a terphenyl group.

In one embodiment, L₁ may be selected from:

a benzene group, a naphthalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a naphthofluorene group,a pyridine group, a pyrimidine group, a pyridazine group, a triazinegroup, a pyrrole group, a thiophene group, a furan group, an imidazolegroup, a pyrazole group, an oxazole group, an isoxazole group, athiazole group, an isoxazole group, a triazole group, a carbazole group,a dibenzofuran group, and a dibenzothiophene group; and

a benzene group, a naphthalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a naphthofluorene group,a pyridine group, a pyrimidine group, a pyridazine group, a triazinegroup, a pyrrole group, a thiophene group, a furan group, an imidazolegroup, a pyrazole group, an oxazole group, an isoxazole group, athiazole group, an isoxazole group, a triazole group, a carbazole group,a dibenzofuran group, and a dibenzothiophene group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a methyl group, an ethyl group, a propylgroup, an isobutyl group, a sec-butyl group, a ter-butyl group, a pentylgroup, an iso-amyl group, a hexyl group, a C₁-C₂₀ alkoxy group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopentenyl group, a cyclohexenyl group, a phenyl group, and anaphthyl group,

R₁ may be selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, —Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a methyl group, anethyl group, a propyl group, an isobutyl group, a sec-butyl group, ater-butyl group, a pentyl group, an iso-amyl group, a hexyl group, and aC₁-C₂₀ alkoxy group; and

—Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a methyl group, an ethyl group, apropyl group, an isobutyl group, a sec-butyl group, a ter-butyl group, apentyl group, an iso-amyl group, and a hexyl group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a methyl group, an ethyl group, a propylgroup, an isobutyl group, a sec-butyl group, a ter-butyl group, a pentylgroup, an iso-amyl group, and a hexyl group, and

Q₃₁ to Q₃₃ may each independently be selected from hydrogen, deuterium,—F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, anamidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀ alkylgroup, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, aC₆-C₆₀ aryl group, a C₆-C₆₀ aryl group substituted with a C₁-C₆₀ alkylgroup, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensedpolycyclic group, a monovalent non-aromatic condensed heteropolycyclicgroup, a biphenyl group, and a terphenyl group.

In one embodiment, a1 may be an integer from 0 to 5.

In one embodiment, b1 may be an integer from 1 to 5.

In one embodiment, a1 may be 1 or 2.

In one embodiment, R₄ may be selected from a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, and a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group.

In one embodiment, R₄ may be a substituted or unsubstituted C₆-C₁₀ arylgroup or a substituted or unsubstituted C₅-C₁₀ heteroaryl group.

In one embodiment, R₄ may be represented by Formula 3:

In Formula 3,

X₂₁ to X₂₅ may each independently be N or CR₃, and

* indicates a binding site to a neighboring atom.

In one embodiment, none of or one to three of X₂₁ to X₂₅ may be N.

In one embodiment, all of X₂₁ to X₂₅ may be CR₃.

In one embodiment, one to three of X₂₁ to X₂₅ may be N.

In one embodiment, in Formula 2, none of or one to three of X₁₁ to X₁₄may be N.

In one embodiment, all of X₁₁ to X₁₄ may be CR₃.

In one embodiment, one to three of X₁₁ to X₁₄ may be N.

In one embodiment, in Formula 2, none of or one to three of X₁₅ to X₁₈may be N.

In one embodiment, all of X₁₅ to X₁₈ may be CR₃.

In one embodiment, one to three of X₁₅ to X₁₈ may be N.

In one embodiment, R₁₁ to R₁₆ may each independently be selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, —Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a substituted orunsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, anda substituted or unsubstituted C₁-C₆₀ alkoxy group, where neighboringsubstituents may optionally be linked to form a substituted orunsubstituted ring.

In one embodiment, when neighboring substituents in R₁₁ to R₁₆ arelinked to form a substituted or unsubstituted ring, the substituted orunsubstituted ring may be selected from a substituted or unsubstitutedcyclopentane, a substituted or unsubstituted cyclohexane, a substitutedor unsubstituted benzene, and a substituted or unsubstituted fluorene.

In one embodiment, when neighboring substituents in R₁₁ to R₁₆ arelinked to form a substituted or unsubstituted ring, R₁₂ and R₁₃ may belinked to form a substituted or unsubstituted ring.

In one embodiment, the heterocyclic compound represented by Formula 1may be selected from the following Compounds 1 to 75:

When the heterocyclic compound of the present embodiments satisfies thespecific structure of Formula 1, the heterocyclic compound may have ahigh glass transition temperature, and an appropriate steric hindranceeffect, and the heterocyclic compound may maintain high triplet energyof a molecule at a high level, and thus, the heterocyclic compound maybe used as a phosphorescent host.

Therefore, an electronic device, for example, an organic light-emittingdevice, which includes the heterocyclic compound, may have a low drivingvoltage, high current density, and high efficiency.

Also, the heterocyclic compound represented by Formula 1 is capable ofemitting delayed fluorescence, and a triplet exciton, as well as asinglet exciton, may be used for light emission according to anappropriate combination of substituents. Thus, an organic light-emittingdevice including the heterocyclic compound may have excellent (orsuitable) luminescent efficiency.

In one embodiment, at least one substituent of the substituted C₅-C₆₀carbocyclic group, the substituted C₁-C₆₀ heterocyclic group, thesubstituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group,the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxygroup, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, thesubstituted C₁-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ arylgroup, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀arylthio group, the substituted C₁-C₆₀ heteroaryl group, the substitutedmonovalent non-aromatic condensed polycyclic group, and the substitutedmonovalent non-aromatic condensed heteropolycyclic group may be selectedfrom:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and aC₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with deuterium, —F, —Cl,—Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₃-C₁₀ cycloalkyl group,a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group, a biphenylgroup, and a terphenyl group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group, a biphenylgroup, and a terphenyl group, each substituted with at least oneselected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amidino group, a hydrazino group, a hydrazonogroup, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, a biphenyl group, and a terphenylgroup; and

—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q₃₁ to Q₃₃ may each independently be selected from hydrogen, deuterium,—F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, anamidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀ alkylgroup, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxygroup, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, aC₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀aryl group, a C₆-C₆₀ aryl group substituted with a C₁-C₆₀ alkyl group, aC₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclicgroup, a monovalent non-aromatic condensed heteropolycyclic group, abiphenyl group, and a terphenyl group.

Another embodiment provides an organic light-emitting device including:a first electrode; a second electrode facing the first electrode; and anorganic layer between the first electrode and the second electrode andincluding an emission layer, wherein the organic layer may include atleast one heterocyclic compound of the present embodiments.

In one embodiment, the first electrode may be an anode.

In one embodiment, the second electrode may be a cathode.

In one embodiment, the first electrode may be an anode, and the secondelectrode may be a cathode.

In one embodiment, the organic layer may further include a holetransport region between the first electrode and the emission layer, andan electron transport region between the emission layer and the secondelectrode.

In one embodiment, the hole transport region may include at least onelayer selected from a hole injection layer, a hole transport layer, anemission auxiliary layer, and an electron blocking layer.

In one embodiment, the electron transport region may include at leastone selected from a hole blocking layer, an electron transport layer,and an electron injection layer.

In one or more embodiments, the emission layer may include the condensedheterocyclic compound represented by Formula 1.

In one embodiment, the emission layer may be a phosphorescent or delayedfluorescent emission layer.

In one embodiment, the emission layer may further include a phosphineoxide-based compound.

In one embodiment, the electron transport region may further include aphosphine oxide-based compound.

In one embodiment, the hole injection layer may include an amine-basedcompound.

In one embodiment, the heterocyclic compound included in the emissionlayer may be a host, and the emission layer may further include aphosphorescent dopant.

In one embodiment, the heterocyclic compound included in the emissionlayer may be a host, and the emission layer may further include adelayed fluorescent dopant satisfying Equation 1 below.|E _(D, S1) −E _(D, T1)|≤0.3 eV.  Equation 1

In Equation 1,

E_(D, S1) is singlet energy (eV) of the delayed fluorescent dopant, and

E_(D, T1) is triplet energy (eV) of the delayed fluorescent dopant.

Since a difference between the singlet energy (E_(D, S1)) and thetriplet energy (E_(D, T1)) of the delayed fluorescent dopant is 0.3 eVor less, a singlet exciton and a triplet exciton produced by an electricfield may easily transit to an intermediate state.

In one or more embodiments, the heterocyclic compound included in theemission layer may be a delayed fluorescent dopant and may satisfyEquation 1.|E _(D, S1) −E _(D, T1)|≤0.3 eV.  Equation 1

In Equation 1,

E_(D, S1) is singlet energy (eV) of the delayed fluorescent dopant, and

E_(D, T1) is triplet energy (eV) of the delayed fluorescent dopant.

Since a difference between the singlet energy (E_(D, S1)) and thetriplet energy (E_(D, T1)) of the delayed fluorescent dopant is 0.3 eVor less, a singlet exciton and a triplet exciton produced by an electricfield may easily transit to an intermediate state.

In one or more embodiments, the heterocyclic compound included in theemission layer may be a delayed fluorescent dopant, the emission layermay further include a host, and the delayed fluorescent dopant and thehost may satisfy Equation 2 or 3 below.|E _(H, HOMO) −E _(D, HOMO)|≤0.5 eV  Equation 2|E _(H, LUMO) −E _(D, LUMO)|≤0.5 eV.  Equation 3

In Equations 2 and 3,

E_(H, HOMO) is a highest occupied molecular orbital (HOMO) energy levelof the host,

E_(D, HOMO) is a HOMO energy level of the dopant,

E_(H, LUMO) is a lowest unoccupied molecular orbital (LUMO) energy levelof the host, and

E_(D, LUMO) is a LUMO energy level of the dopant.

Since a difference in HOMO energy level or LUMO energy level between thedelayed fluorescent dopant, that is, the heterocyclic compound, and thehost is 0.5 eV or less, charge transfer from the host to the delayedfluorescent dopant is facilitated. Accordingly, an organiclight-emitting device including the heterocyclic compound as the delayedfluorescent dopant may have excellent luminescent efficiency.

For example, the host may further include a silicon-based compound, acarbazole-based compound, or a phosphine oxide-based compound.

According to an embodiment, the host may be one of Compounds H101 toH106 below:

In one or more embodiments, at least one layer selected from theelectron transport layer and the electron injection layer may include analkali metal, an alkaline earth metal, a rare earth metal, an alkalimetal compound, an alkaline earth-metal compound, a rare earth metalcompound, an alkali metal complex, an alkaline earth-metal complex, arare earth metal complex, or any combination thereof.

The organic light-emitting device may have, due to the inclusion of theheterocyclic compound, a low driving voltage, high current density, andhigh luminescent efficiency.

A method of synthesizing the heterocyclic compound of the presentembodiments and the method of manufacturing the organic light-emittingdevice including the same should be apparent to those of ordinary skillby referring to Examples provided below, but embodiments of the presentdisclosure are not limited thereto.

In addition to the compounds described above, other compounds known inthe art may be used between a pair of electrodes of the organiclight-emitting device. For example, other compounds may be included inat least one of the hole transport region and the emission layer. In oneembodiment, other compounds may be used as a material for forming acapping layer disposed outside the pair of electrodes of the organiclight-emitting device.

According to one or more embodiments of the present disclosure, anorganic light-emitting device includes a first electrode; a secondelectrode facing the first electrode, and an organic layer that isdisposed (e.g., positioned) between the first electrode and the secondelectrode and includes at least one heterocyclic compound of Formula 1described above.

The expression “(an organic layer) includes at least one heterocycliccompound represented by Formula 1” as used herein may refer to a case inwhich “(an organic layer) includes one or more identical heterocycliccompounds represented by Formula 1” and a case in which “(an organiclayer) includes two or more different heterocyclic compounds representedby Formula 1.”

For example, the organic layer may include, as the heterocycliccompound, only Compound 1. In this regard, Compound 1 may be included inan emission layer of the organic light-emitting device. In one or moreembodiments, the organic layer may include, as the heterocycliccompound, Compound 1 and Compound 2. In this regard, Compound 1 andCompound 2 may both be included in the same layer (for example, Compound1 and Compound 2 may both be included in an emission layer), ordifferent layers (for example, Compound 1 may be in an emission layerand Compound 2 may be in an electron transport layer).

The term “organic layer” as used herein may refer to a single layerand/or a plurality of layers disposed between the first electrode andthe second electrode of an organic light-emitting device. A materialincluded in the “organic layer” is not limited to an organic material.

The FIG. is a schematic view of an organic light-emitting device 10according to an embodiment. The organic light-emitting device 10includes a first electrode 110, an organic layer 150, and a secondelectrode 190.

Hereinafter, the structure of the organic light-emitting device 10according to an embodiment and a method of manufacturing the organiclight-emitting device 10 will be described in connection with theFIGURE.

Referring to the FIGURE, a substrate may be additionally disposed underthe first electrode 110 or above the second electrode 190. The substratemay be a glass substrate or a plastic substrate, each having excellentmechanical strength, thermal stability, transparency, surfacesmoothness, ease of handling, and/or water resistance.

The first electrode 110 may be formed by depositing or sputtering amaterial for forming the first electrode 110 on the substrate. When thefirst electrode 110 is an anode, the material for forming the firstelectrode 110 may be selected from materials with a high work functionto facilitate hole injection.

The first electrode 110 may be a reflective electrode, asemi-transmissive electrode, or a transmissive electrode. When the firstelectrode 110 is a transmissive electrode, a material for forming thefirst electrode may be selected from indium tin oxide (ITO), indium zincoxide (IZO), tin oxide (SnO₂), zinc oxide (ZnO), and any combinationsthereof, but embodiments of the present disclosure are not limitedthereto. In one or more embodiments, when the first electrode 110 is asemi-transmissive electrode or a reflective electrode, a material forforming the first electrode may be selected from magnesium (Mg), silver(Ag), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca),magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), and any combinationsthereof, but embodiments of the present disclosure are not limitedthereto.

The first electrode 110 may have a single-layered structure, or amulti-layered structure including two or more layers. For example, thefirst electrode 110 may have a three-layered structure of ITO/Ag/ITO,but the structure of the first electrode 110 is not limited thereto.

The organic layer 150 may be disposed on the first electrode 110. Theorganic layer 150 may include a first organic layer.

In one embodiment, the first organic layer may include an emissionlayer.

In one embodiment, the organic layer 150 may further include a secondorganic layer between the first organic layer and the second electrode190. For example, the second organic layer may include an electrontransport region.

The organic layer 150 may further include a hole transport regionbetween the first electrode 110 and the emission layer. In oneembodiment, the organic layer 150 may include a hole transport regionbetween the first electrode 110 and the emission layer and an electrontransport region between the emission layer and the second electrode190.

The hole transport region may have i) a single-layered structureincluding a single layer including a single material, ii) asingle-layered structure including a single layer including a pluralityof different materials, or iii) a multi-layered structure having aplurality of layers including a plurality of different materials.

The hole transport region may include at least one layer selected from ahole injection layer, a hole transport layer, an emission auxiliarylayer, and an electron blocking layer.

In an embodiment, the hole transport region may have a single-layeredstructure including a single layer including a plurality of differentmaterials, or a multi-layered structure, for example, a hole injectionlayer/hole transport layer structure, a hole injection layer/holetransport layer/emission auxiliary layer structure, a hole injectionlayer/emission auxiliary layer structure, a hole transportlayer/emission auxiliary layer structure, or a hole injection layer/holetransport layer/electron blocking layer structure, wherein for eachstructure, constituting layers are sequentially stacked from the firstelectrode 110 in this stated order, but the structure of the holetransport region is not limited thereto.

The hole transport region may include at least one selected fromm-MTDATA, TDATA, 2-TNATA, NPB(NPD), β-NPB, TPD, Spiro-TPD, Spiro-NPB,methylated NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine(TCTA), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA),poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS),polyaniline/camphor sulfonic acid (PANT/CSA),polyaniline/poly(4-styrenesulfonate) (PANT/PSS), a compound representedby Formula 201, and a compound represented by Formula 202:

In Formulae 201 and 202,

L₂₀₁ to L₂₀₄ may each independently be selected from a substituted orunsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group,

L₂₀₅ may be selected from *—O—*′, *—S—*′, *—N(Q₂₀₁)-*′, a substituted orunsubstituted C₁-C₂₀ alkylene group, a substituted or unsubstitutedC₂-C₂₀ alkenylene group, a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group,

xa1 to xa4 may each independently be an integer from 0 to 3,

xa5 may be an integer from 1 to 10, and

R₂₀₁ to R₂₀₄ and Q₂₀₁ may each independently be selected from asubstituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted orunsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, and a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group.

In one embodiment, in Formula 202, R₂₀₁ and R₂₀₂ may optionally belinked via a single bond, a dimethyl-methylene group, or adiphenyl-methylene group, and R₂₀₃ and R₂₀₄ may optionally be linked viaa single bond, a dimethyl-methylene group, or a diphenyl-methylenegroup.

In one embodiment, in Formulae 201 and 202,

L₂₀₁ to L₂₀₅ may each independently be selected from:

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anindacenylene group, an acenaphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenalenylene group, a phenanthrenylenegroup, an anthracenylene group, a fluoranthenylene group, atriphenylenylene group, a pyrenylene group, a chrysenylene group, anaphthacenylene group, a picenylene group, a perylenylene group, apentaphenylene group, a hexacenylene group, a pentacenylene group, arubicenylene group, a coronenylene group, an ovalenylene group, athiophenylene group, a furanylene group, a carbazolylene group, anindolylene group, an isoindolylene group, a benzofuranylene group, abenzothiophenylene group, a dibenzofuranylene group, adibenzothiophenylene group, a benzocarbazolylene group, adibenzocarbazolylene group, a dibenzosilolylene group, and apyridinylene group; and

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anindacenylene group, an acenaphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenalenylene group, a phenanthrenylenegroup, an anthracenylene group, a fluoranthenylene group, atriphenylenylene group, a pyrenylene group, a chrysenylene group, anaphthacenylene group, a picenylene group, a perylenylene group, apentaphenylene group, a hexacenylene group, a pentacenylene group, arubicenylene group, a coronenylene group, an ovalenylene group, athiophenylene group, a furanylene group, a carbazolylene group, anindolylene group, an isoindolylene group, a benzofuranylene group, abenzothiophenylene group, a dibenzofuranylene group, adibenzothiophenylene group, a benzocarbazolylene group, adibenzocarbazolylene group, a dibenzosilolylene group, and apyridinylene group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group,a phenyl group, a biphenyl group, a terphenyl group, a phenyl groupsubstituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with—F, a pentalenyl group, an indenyl group, a naphthyl group, an azulenylgroup, a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, athiophenyl group, a furanyl group, a carbazolyl group, an indolyl group,an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinylgroup, —Si(Q₃₁)(Q₃₂)(Q₃₃), and —N(Q₃₁)(Q₃₂), and

Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group,a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group.

In one or more embodiments, xa1 to xa4 may each independently be 0, 1,or 2.

In one or more embodiments, xa5 may be 1, 2, 3, or 4.

In one or more embodiments, R₂₀₁ to R₂₀₄ and Q₂₀₁ may each independentlybe selected from:

a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group,an indenyl group, a naphthyl group, an azulenyl group, a heptalenylgroup, an indacenyl group, an acenaphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenalenyl group, a phenanthrenyl group, an anthracenyl group,a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, achrysenyl group, a naphthacenyl group, a picenyl group, a perylenylgroup, a pentaphenyl group, a hexacenyl group, a pentacenyl group, arubicenyl group, a coronenyl group, an ovalenyl group, a thiophenylgroup, a furanyl group, a carbazolyl group, an indolyl group, anisoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, and apyridinyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group,an indenyl group, a naphthyl group, an azulenyl group, a heptalenylgroup, an indacenyl group, an acenaphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenalenyl group, a phenanthrenyl group, an anthracenyl group,a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, achrysenyl group, a naphthacenyl group, a picenyl group, a perylenylgroup, a pentaphenyl group, a hexacenyl group, a pentacenyl group, arubicenyl group, a coronenyl group, an ovalenyl group, a thiophenylgroup, a furanyl group, a carbazolyl group, an indolyl group, anisoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, and apyridinyl group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group,a phenyl group, a biphenyl group, a terphenyl group, a phenyl groupsubstituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with—F, a pentalenyl group, an indenyl group, a naphthyl group, an azulenylgroup, a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, athiophenyl group, a furanyl group, a carbazolyl group, an indolyl group,an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinylgroup, —Si(Q₃₁)(Q₃₂)(Q₃₃), and —N(Q₃₁)(Q₃₂), and

Q₃₁ to Q₃₃ are the same as described above.

In one or more embodiments, at least one of R₂₀₁ to R₂₀₃ in Formula 201may each independently be selected from:

a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group, adibenzofuranyl group, and a dibenzothiophenyl group; and

a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group, adibenzofuranyl group, and a dibenzothiophenyl group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenylgroup, a terphenyl group, a phenyl group substituted with a C₁-C₁₀ alkylgroup, a phenyl group substituted with —F, a naphthyl group, a fluorenylgroup, a spiro-bifluorenyl group, a carbazolyl group, a dibenzofuranylgroup, and a dibenzothiophenyl group,

but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, in Formula 202, i) R₂₀₁ and R₂₀₂ may belinked via a single bond, and/or ii) R₂₀₃ and R₂₀₄ may be linked via asingle bond.

In one or more embodiments, at least one of R₂₀₁ to R₂₀₄ in Formula 202may be selected from:

a carbazolyl group; and

a carbazolyl group substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group,a phenyl group, a biphenyl group, a terphenyl group, a phenyl groupsubstituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with—F, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, acarbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group,

but embodiments of the present disclosure are not limited thereto.

The compound represented by Formula 201 may be represented by Formula201A:

In one embodiment, the compound represented by Formula 201 may berepresented by Formula 201A(1) below, but embodiments of the presentdisclosure are not limited thereto:

In one embodiment, the compound represented by Formula 201 may berepresented by Formula 201A-1 below, but embodiments of the presentdisclosure are not limited thereto:

In one embodiment, the compound represented by Formula 202 may berepresented by Formula 202A:

In one embodiment, the compound represented by Formula 202 may berepresented by Formula 202A-1:

In Formulae 201A, 201A(1), 201A-1, 202A, and 202A-1,

descriptions of L₂₀₁ to L₂₀₃, xa1 to xa3, xa5, and R₂₀₂ to R₂₀₄ arerespectively the same as those provided above,

descriptions for R₂₁₁ and R₂₁₂ may each independently be understood byreferring to the description provided herein in connection with R₂₀₃,and

R₂₁₃ to R₂₁₇ may each independently be selected from hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group,a phenyl group, a biphenyl group, a terphenyl group, a phenyl groupsubstituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with—F, a pentalenyl group, an indenyl group, a naphthyl group, an azulenylgroup, a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, athiophenyl group, a furanyl group, a carbazolyl group, an indolyl group,an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, and apyridinyl group.

The hole transport region may include at least one compound selectedfrom Compounds HT1 to HT39, but embodiments of the present disclosureare not limited thereto:

A thickness of the hole transport region may be in a range of about 100Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å. When thehole transport region includes at least one of a hole injection layerand a hole transport layer, a thickness of the hole injection layer maybe in a range of about 100 Å to about 9,000 Å, for example, about 100 Åto about 1,000 Å, and a thickness of the hole transport layer may be ina range of about 50 Å to about 2,000 Å, for example about 100 Å to about1,500 Å. When the thicknesses of the hole transport region, the holeinjection layer, and the hole transport layer are within any of theseranges, satisfactory (or suitable) hole transporting characteristics maybe obtained without a substantial increase in driving voltage.

The emission auxiliary layer may increase light-emission efficiency bycompensating for an optical resonance distance according to thewavelength of light emitted by an emission layer, and the electronblocking layer may block or reduce the flow of electrons from anelectron transport region. The emission auxiliary layer and the electronblocking layer may each independently include any of the materialsdescribed above.

The hole transport region may further include, in addition to thematerials described above, a charge-generation material for theimprovement of conductive properties. The charge-generation material maybe homogeneously or non-homogeneously dispersed in the hole transportregion.

The charge-generation material may be, for example, a p-dopant.

In one embodiment, the p-dopant may have a lowest unoccupied molecularorbital (LUMO) of about −3.5 eV or less.

The p-dopant may include at least one selected from a quinonederivative, a metal oxide, and a cyano group-containing compound, butembodiments of the present disclosure are not limited thereto.

For example, the p-dopant may include at least one selected from:

a quinone derivative, such as tetracyanoquinodimethane (TCNQ) and/or2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ);

a metal oxide, such as tungsten oxide and/or molybdenum oxide;

1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN); and

a compound represented by Formula 221 below:

but embodiments of the present disclosure are not limited thereto:

In Formula 221,

R₂₂₁ to R₂₂₃ may each independently be selected from a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, asubstituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted monovalentnon-aromatic condensed heteropolycyclic group, wherein at least oneselected from R₂₂₁ to R₂₂₃ may have at least one substituent selectedfrom a cyano group, —F, —Cl, —Br, —I, a C₁-C₂₀ alkyl group substitutedwith —F, a C₁-C₂₀ alkyl group substituted with —Cl, a C₁-C₂₀ alkyl groupsubstituted with Br, and a C₁-C₂₀ alkyl group substituted with —I.

When the organic light-emitting device 10 is a full-color organiclight-emitting device, the emission layer may be patterned into a redemission layer, a green emission layer, or a blue emission layer,according to a sub-pixel. In one or more embodiments, the emission layermay have a stacked structure of two or more layers selected from a redemission layer, a green emission layer, and a blue emission layer, inwhich the two or more layers contact each other or are separated fromeach other. In one or more embodiments, the emission layer may includetwo or more materials selected from a red light-emitting material, agreen light-emitting material, and a blue light-emitting material, inwhich the two or more materials are mixed with each other in a singlelayer to emit white light.

The emission layer may include a host and a dopant. The dopant mayinclude at least one selected from a phosphorescent dopant and afluorescent dopant.

In one embodiment, the dopant may include the second compoundrepresented by Formula 2. In one embodiment, the dopant may include thesecond compound represented by Formula 2 as a fluorescent dopant.

An amount of the dopant in the emission layer may be in a range of about0.01 parts by weight to about 15 parts by weight based on 100 parts byweight of the host, but embodiments of the present disclosure are notlimited thereto.

A thickness of the emission layer may be in a range of about 100 Å toabout 1,000 Å, for example, about 200 Å to about 600 Å. When thethickness of the emission layer is within this range, excellentlight-emission characteristics may be obtained without a substantialincrease in driving voltage.

The host may include the heterocyclic compound represented by Formula 1.

In one or more embodiments, the host may include a silicon-basedcompound, a carbazole-based compound, and/or a phosphine oxide-basedcompound. For example, the host may be one of Compounds H101 to H106below:

In one or more embodiments, the host may include a compound representedby Formula 301 below.[Ar₃₀₁]_(xb11)-[(L₃₀₁)_(xb1)-R₃₀₁]_(xb21).  Formula 301

In Formula 301,

Ar₃₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group ora substituted or unsubstituted C₁-C₆₀ heterocyclic group,

xb11 may be 1, 2, or 3,

L₃₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group,

xb1 may be an integer from 0 to 5,

R₃₀₁ may be selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group,a cyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a substituted or unsubstituted C₁-C₆₀ alkyl group, asubstituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted orunsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstitutedC₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkylgroup, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃), —N(Q₃₀₁)(Q₃₀₂),—B(Q₃₀₁)(Q₃₀₂), —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), and —P(═O)(Q₃₀₁)(Q₃₀₂),

xb21 may be an integer from 1 to 5, and

Q₃₀₁ to Q₃₀₃ may each independently be selected from a C₁-C₁₀ alkylgroup, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group, but embodiments of the presentdisclosure are not limited thereto.

In one embodiment, Ar₃₀₁ in Formula 301 may be selected from:

a naphthalene group, a fluorene group, a spiro-bifluorene group, abenzofluorene group, a dibenzofluorene group, a phenalene group, aphenanthrene group, an anthracene group, a fluoranthene group, atriphenylene group, a pyrene group, a chrysene group, a naphthacenegroup, a picene group, a perylene group, a pentaphene group, anindenoanthracene group, a dibenzofuran group, and a dibenzothiophenegroup; and

a naphthalene group, a fluorene group, a spiro-bifluorene group, abenzofluorene group, a dibenzofluorene group, a phenalene group, aphenanthrene group, an anthracene group, a fluoranthene group, atriphenylene group, a pyrene group, a chrysene group, a naphthacenegroup, a picene group, a perylene group, a pentaphene group, anindenoanthracene group, a dibenzofuran group, and a dibenzothiophenegroup, each substituted with at least one selected from deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, aC₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),—C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group,a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group, but embodiments of the present disclosureare not limited thereto.

When xb11 in Formula 301 is two or more, two or more Ar₃₀₁(s) may belinked via a single bond.

In one or more embodiments, the compound represented by Formula 301 maybe represented by Formula 301-1 or Formula 301-2:

In Formulae 301-1 and 301-2,

A₃₀₁ to A₃₀₄ may each independently be selected from a benzene, anaphthalene, a phenanthrene, a fluoranthene, a triphenylene, a pyrene, achrysene, a pyridine, a pyrimidine, an indene, a fluorene, aspiro-bifluorene, a benzofluorene, a dibenzofluorene, an indole, acarbazole, a benzocarbazole, a dibenzocarbazole, a furan, a benzofuran,a dibenzofuran, a naphthofuran, a benzonaphthofuran, a dinaphthofuran, athiophene, a benzothiophene, a dibenzothiophene, a naphthothiophene, abenzonaphthothiophene group, and a dinaphthothiophene group,

X₃₀₁ may be O, S, or N-[(L₃₀₄)_(xb4)-R₃₀₄],

R₃₁₁ to R₃₁₄ may each independently be selected from hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),—B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

xb22 and xb23 may each independently be 0, 1, or 2,

L₃₀₁, xb1, R₃₀₁, and Q₃₁ to Q₃₃ are the same as described above,

descriptions of L₃₀₂ to L₃₀₄ may each independently be the same as thatprovided in connection with L₃₀₁,

descriptions of xb2 to xb4 may each independently be the same as thatprovided in connection with xb1, and

descriptions of R₃₀₂ to R₃₀₄ may each independently be the same as thatprovided in connection with R₃₀₁.

For example, L₃₀₁ to L₃₀₄ in Formulae 301, 301-1, and 301-2 may eachindependently be selected from:

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazolylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group; and

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazolylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, anaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group,an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenylgroup, a hexacenyl group, a pentacenyl group, a thiophenyl group, afuranyl group, a carbazolyl group, an indolyl group, an isoindolylgroup, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranylgroup, a dibenzothiophenyl group, a benzocarbazolyl group, adibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, anoxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, a triazinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, aphenanthridinyl group, an acridinyl group, a phenanthrolinyl group, aphenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, abenzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinylgroup, an azacarbazolyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),—B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q₃₁ to Q₃₃ are the same as described above.

In one embodiment, R₃₀₁ to R₃₀₄ in Formulae 301, 301-1, and 301-2 mayeach independently be selected from:

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothtophenyl group, a di benzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyndinyl group, an imidazopynmidinyl group, and anazacarbazolyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, aperylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a thiophenyl group, a furanyl group, a carbazolyl group, anindolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, an azacarbazolylgroup, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q₃₁ to Q₃₃ are the same as described above.

In one or more embodiments, the host may include an alkaline earth metalcomplex. For example, the host may be selected from a Be complex (e.g.,Compound H55), a Mg complex, and a Zn complex.

The host may include at least one selected from9,10-di(2-naphthyl)anthracene (ADN),2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN),9,10-di-(2-naphthyl)-2-t-butyl-anthracene (TBADN),4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), 1,3-di-9-carbazolylbenzene(mCP), 1,3,5-tri(carbazol-9-yl)benzene (TCP), and Compounds H1 to H55,but embodiments of the present disclosure are not limited thereto:

The phosphorescent dopant may include an organometallic complexrepresented by Formula 401 below:

In Formulae 401 and 402,

M may be selected from iridium (Ir), platinum (Pt), palladium (Pd),osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu),terbium (Tb), rhodium (Rh), and thulium (Tm),

L₄₀₁ may be selected from ligands represented by Formula 402, and xc1may be 1, 2, or 3, wherein, when xc1 is two or more, two or more L₄₀₁(s)may be identical to or different from each other,

L₄₀₂ may be an organic ligand, and xc2 may be an integer from 0 to 4,wherein, when xc2 is two or more, two or more L₄₀₂(s) may be identicalto or different from each other,

X₄₀₁ to X₄₀₄ may each independently be nitrogen or carbon,

X₄₀₁ and X₄₀₃ may be linked via a single bond or a double bond, and X₄₀₂and X₄₀₄ may be linked via a single bond or a double bond,

A₄₀₁ and A₄₀₂ may each independently be a C₅-C₆₀ carbocyclic group or aC₁-C₆₀ heterocyclic group,

X₄₀₅ may be a single bond, *—O—*′, *—S—*′, *—C(═O)—*′, *—N(Q₄₁₁)-*′,*—C(Q₄₁₁)(Q₄₁₂)-*′, *—C(Q₄₁₁)═C(Q₄₁₂)-*′, *—C(Q₄₁₁)=*′, or *═C(Q₄₁₁)=*′,and Q₄₁₁ and Q₄₁₂ may each independently be hydrogen, deuterium, aC₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenylgroup, a terphenyl group, or a naphthyl group,

X₄₀₆ may be a single bond, O, or S,

R₄₀₁ and R₄₀₂ may each independently be selected from hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, asubstituted or unsubstituted C₁-C₂₀ alkyl group, a substituted orunsubstituted C₁-C₂₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, a substituted or unsubstituted monovalent non-aromaticcondensed heteropolycyclic group, —Si(Q₄₀₁)(Q₄₀₂)(Q₄₀₃), —N(Q₄₀₁)(Q₄₀₂),—B(Q₄₀₁)(Q₄₀₂), —C(═O)(Q₄₀₁), —S(═O)₂(Q₄₀₁), and —P(═O)(Q₄₀₁)(Q₄₀₂), andQ₄₀₁ to Q₄₀₃ may each independently be selected from a C₁-C₁₀ alkylgroup, a C₁-C₁₀ alkoxy group, a C₆-C₂₀ aryl group, and a C₁-C₂₀heteroaryl group,

xc11 and xc12 may each independently be an integer from 0 to 10, and

* and *′ in Formula 402 each indicate a binding site to M in Formula401.

In one embodiment, A₄₀₁ and A₄₀₂ in Formula 402 may each independentlybe selected from a benzene group, a naphthalene group, a fluorene group,a spiro-bifluorene group, an indene group, a pyrrole group, a thiophenegroup, a furan group, an imidazole group, a pyrazole group, a thiazolegroup, an isothiazole group, an oxazole group, an isoxazole group, apyridine group, a pyrazine group, a pyrimidine group, a pyridazinegroup, a quinoline group, an isoquinoline group, a benzoquinoline group,a quinoxaline group, a quinazoline group, a carbazole group, abenzimidazole group, a benzofuran group, a benzothiophene group, anisobenzothiophene group, a benzoxazole group, an isobenzoxazole group, atriazole group, a tetrazole group, an oxadiazole group, a triazinegroup, a dibenzofuran group, and a dibenzothiophene group.

In one or more embodiments, in Formula 402, i) X₄₀₁ may be nitrogen, andX₄₀₂ may be carbon, or ii) X₄₀₁ and X₄₀₂ may each be nitrogen at thesame time.

In one or more embodiments, R₄₀₁ and R₄₀₂ in Formula 402 may eachindependently be selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a phenyl group, a naphthyl group, a cyclopentyl group,a cyclohexyl group, an adamantanyl group, a norbornanyl group, and anorbornenyl group;

a cyclopentyl group, a cyclohexyl group, an adamantanyl group, anorbornanyl group, a norbornenyl group, a phenyl group, a biphenylgroup, a terphenyl group, a naphthyl group, a fluorenyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, a triazinyl group, a quinolinyl group, an isoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a carbazolyl group, adibenzofuranyl group, and a dibenzothiophenyl group;

a cyclopentyl group, a cyclohexyl group, an adamantanyl group, anorbornanyl group, a norbornenyl group a phenyl group, a biphenyl group,a terphenyl group, a naphthyl group, a fluorenyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, atriazinyl group, a quinolinyl group, an isoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a carbazolyl group, adibenzofuranyl group, and a dibenzothiophenyl group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, acyclopentyl group, a cyclohexyl group, an adamantanyl group, anorbornanyl group, a norbornenyl group, a phenyl group, a biphenylgroup, a terphenyl group, a naphthyl group, a fluorenyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, a triazinyl group, a quinolinyl group, an isoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a carbazolyl group, adibenzofuranyl group, and a dibenzothiophenyl group; and

—Si(Q₄₀₁)(Q₄₀₂)(Q₄₀₃), —N(Q₄₀₁)(Q₄₀₂), —B(Q₄₀₁)(Q₄₀₂), —C(═O)(Q₄₀₁),S(═O)₂(Q₄₀₁), and —P(═O)(Q₄₀₁)(Q₄₀₂), and

Q₄₀₁ to Q₄₀₃ may each independently be selected from a C₁-C₁₀ alkylgroup, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, and anaphthyl group, but embodiments of the present disclosure are notlimited thereto.

In one or more embodiments, when xc1 in Formula 401 is two or more, twoA₄₀₁(s) in two or more L₄₀₁(s) may optionally be linked via X₄₀₇, whichis a linking group, or two A₄₀₂(s) in two or more L₄₀₁(s) may optionallybe linked via X₄₀₈, which is a linking group (see e.g., Compounds PD1 toPD4 and PD7). X₄₀₇ and X₄₀₈ may each independently be a single bond,*—O—*′, *—S—*′, *—C(═O)—*′, *—N(Q₄₁₃)-*′, *—C(Q₄₁₃)(Q₄₁₄)-*′, or*—C(Q₄₁₃)═C(Q₄₁₄)-*′ (wherein Q₄₁₃ and Q₄₁₄ may each independently behydrogen, deuterium, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, aphenyl group, a biphenyl group, a terphenyl group, or a naphthyl group),but embodiments of the present disclosure are not limited thereto.

L₄₀₂ in Formula 401 may be a monovalent, divalent, or trivalent organicligand. For example, L₄₀₂ may be selected from halogen, diketone (e.g.,acetylacetonate), carboxylic acid (e.g., picolinate), —C(═O),isonitrile, —CN, and phosphorus ligands (e.g., phosphine and/orphosphite), but embodiments of the present disclosure are not limitedthereto.

In one or more embodiments, the phosphorescent dopant may be selectedfrom, for example, Compounds PD1 to PD25, but embodiments of the presentdisclosure are not limited thereto:

The fluorescent dopant may include an arylamine compound or astyrylamine compound.

The fluorescent dopant may include a compound represented by Formula 501below:

In Formula 501,

Ar₅₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group ora substituted or unsubstituted C₁-C₆₀ heterocyclic group,

L₅₀₁ to L₅₀₃ may each independently be selected from a substituted orunsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group,

xd1 to xd3 may each independently be an integer from 0 to 3,

R₅₀₁ and R₅₀₂ may each independently be selected from a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, and a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group,and

xd4 may be an integer from 1 to 6.

In one embodiment, Ar₅₀₁ in Formula 501 may be selected from:

a naphthalene group, a heptalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a dibenzofluorene group,a phenalene group, a phenanthrene group, an anthracene group, afluoranthene group, a triphenylene group, a pyrene group, a chrysenegroup, a naphthacene group, a picene group, a perylene group, apentaphene group, an indenoanthracene group, and an indenophenanthrenegroup; and

a naphthalene group, a heptalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a dibenzofluorene group,a phenalene group, a phenanthrene group, an anthracene group, afluoranthene group, a triphenylene group, a pyrene group, a chrysenegroup, a naphthacene group, a picene group, a perylene group, apentaphene group, an indenoanthracene group, and an indenophenanthrenegroup, each substituted with at least one selected from deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, aC₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group.

In one or more embodiments, L₅₀₁ to L₅₀₃ in Formula 501 may eachindependently be selected from:

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, and a pyridinylene group; and

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, and a pyridinylene group, each substituted withat least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, aphenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, and a pyridinyl group.

In one or more embodiments, R₅₀₁ and R₅₀₂ in Formula 501 may eachindependently be selected from:

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, and a pyridinyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, and a pyridinyl group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenylgroup, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, and —Si(Q₃₁)(Q₃₂)(Q₃₃), and

Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group,a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group.

In one or more embodiments, xd4 in Formula 501 may be 2, but embodimentsof the present disclosure are not limited thereto.

For example, the fluorescent dopant may include at least one selectedfrom Compounds FD1 to FD22:

In one or more embodiments, the fluorescent dopant may include at leastone selected from the following compounds, but embodiments of thepresent disclosure are not limited thereto:

The delayed fluorescent dopant may include the heterocyclic compoundrepresented by Formula 1. The delayed fluorescent dopant may satisfyEquation 1 below:|E _(D, S1) −E _(D, T1)|≤0.3 eV.  Equation 1

In Equation 1,

E_(D, S1) is singlet energy (eV) of the delayed fluorescent dopant, and

E_(D, T1) is triplet energy (eV) of the delayed fluorescent dopant.

The delayed fluorescent dopant and the host may satisfy Equation 2 or 3:|E _(H, HOMO) −E _(D, HOMO)|≤0.5 eV  Equation 2|E _(H, LUMO) −E _(D, LUMO)|≤0.5 eV.  Equation 3

In Equations 2 and 3,

E_(H, HOMO) is a HOMO energy level of the host,

E_(D, HOMO) is a HOMO energy level of the dopant,

E_(H, LUMO) is a LUMO energy level of the host, and

E_(D, LUMO) is a LUMO energy level of the dopant.

The electron transport region may have i) a single-layered structureincluding a single layer including a single material, ii) asingle-layered structure including a single layer including a pluralityof different materials, or iii) a multi-layered structure having aplurality of layers including a plurality of different materials.

The electron transport region may include at least one selected from abuffer layer, a hole blocking layer, an electron control layer, anelectron transport layer, and an electron injection layer, butembodiments of the present disclosure are not limited thereto.

For example, the electron transport region may have an electrontransport layer/electron injection layer structure, a hole blockinglayer/electron transport layer/electron injection layer structure, anelectron control layer/electron transport layer/electron injection layerstructure, or a buffer layer/electron transport layer/electron injectionlayer structure, wherein for each structure, constituting layers aresequentially stacked from an emission layer in the stated order.However, embodiments of the structure of the electron transport regionare not limited thereto.

The electron transport region (e.g., a buffer layer, a hole blockinglayer, an electron control layer, and/or an electron transport layer inthe electron transport region) may include a metal-free compoundcontaining at least one π electron-depleted nitrogen-containing ring.

The “π electron-depleted nitrogen-containing ring” may refer to a C₁-C₆₀heterocyclic group having at least one *—N═*′ moiety as a ring-formingmoiety.

For example, the “π electron-depleted nitrogen-containing ring” may bei) a 6-membered to 7-membered heteromonocyclic group having at least one*—N═*′ moiety, ii) a heteropolycyclic group in which two or more5-membered to 7-membered heteromonocyclic groups each having at leastone *—N═*′ moiety are condensed with each other, or iii) aheteropolycyclic group in which at least one of 5-membered to 7-memberedheteromonocyclic groups, each having at least one *—N═*′ moiety, iscondensed with at least one C₅-C₆₀ carbocyclic group.

Examples of the IT electron-depleted nitrogen-containing ring include animidazole, a pyrazole, a thiazole, an isothiazole, an oxazole, anisoxazole, a pyridine, a pyrazine, a pyrimidine, a pyridazine, anindazole, a purine, a quinoline, an isoquinoline, a benzoquinoline, aphthalazine, a naphthyridine, a quinoxaline, a quinazoline, a cinnoline,a phenanthridine, an acridine, a phenanthroline, a phenazine, abenzimidazole, an isobenzothiazole, a benzoxazole, an isobenzoxazole, atriazole, a tetrazole, an oxadiazole, a triazine, thiadiazole, animidazopyridine, an imidazopyrimidine, and an azacarbazole, but are notlimited thereto.

For example, the electron transport region may include a compoundrepresented by Formula 601:[Ar₆₀₁]_(xe11)-[(L₆₀₁)_(xe1)-R₆₀₁]_(xe21).  Formula 601

In Formula 601,

Ar₆₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group ora substituted or unsubstituted C₁-C₆₀ heterocyclic group,

xe11 may be 1, 2 or 3,

L₆₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group,

xe1 may be an integer from 0 to 5,

R₆₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, a substituted or unsubstituted monovalent non-aromaticcondensed heteropolycyclic group, —Si(Q₆₀₁)(Q₆₀₂)(Q₆₀₃), —C(═O)(Q₆₀₁),—S(═O)₂(Q₆₀₁), and —P(═O)(Q₆₀₁N₆₀₂),

Q₆₀₁ to Q₆₀₃ may each independently be a C₁-C₁₀ alkyl group, a C₁-C₁₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or anaphthyl group, and

xe21 may be an integer from 1 to 5.

In one embodiment, at least one selected from xe11 number of Ar₆₀₁ andxe21 number of R₆₀₁ may include the π electron-depletednitrogen-containing ring.

In one embodiment, in Formula 601, ring Ar₆₀₁ may be selected from:

a benzene group, a naphthalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a dibenzofluorene group,a phenalene group, a phenanthrene group, an anthracene group, afluoranthene group, a triphenylene group, a pyrene group, a chrysenegroup, a naphthacene group, a picene group, a perylene group, apentaphene group, an indenoanthracene group, a dibenzofuran group, adibenzothiophene group, a carbazole group, an imidazole group, apyrazole group, a thiazole group, an isothiazole group, an oxazolegroup, an isoxazole group, a pyridine group, a pyrazine group, apyrimidine group, a pyridazine group, an indazole group, a purine group,a quinoline group, an isoquinoline group, a benzoquinoline group, aphthalazine group, a naphthyridine group, a quinoxaline group, aquinazoline group, a cinnoline group, a phenanthridine group, anacridine group, phenanthroline group, phenazine group, a benzimidazolegroup, an iso-benzothiazole group, a benzoxazole group, anisobenzoxazole group, a triazole group, a tetrazole group, an oxadiazolegroup, a triazine group, a thiadiazole group, an imidazopyridine group,an imidazopyrimidine group, and an azacarbazole group; and

a benzene group, a naphthalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a dibenzofluorene group,a phenalene group, a phenanthrene group, an anthracene group, afluoranthene group, a triphenylene group, a pyrene group, a chrysenegroup, a naphthacene group, a picene group, a perylene group, apentaphene group, an indenoanthracene group, a dibenzofuran group, adibenzothiophene group, a carbazole group, an imidazole group, apyrazole group, a thiazole group, an isothiazole group, an oxazolegroup, an isoxazole group, a pyridine group, a pyrazine group, apyrimidine group, a pyridazine group, an indazole group, a purine group,a quinoline group, an isoquinoline group, a benzoquinoline group, aphthalazine group, a naphthyridine group, a quinoxaline group, aquinazoline group, a cinnoline group, a phenanthridine group, anacridine group, phenanthroline group, phenazine group, a benzimidazolegroup, an iso-benzothiazole group, a benzoxazole group, anisobenzoxazole group, a triazole group, a tetrazole group, an oxadiazolegroup, a triazine group, a thiadiazole group, an imidazopyridine group,an imidazopyrimidine group, and an azacarbazole group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, aphenyl group, a biphenyl group, a terphenyl group, a naphthyl group,—Si(Q₃₁)(Q₃₂)(Q₃₃), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group,a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group.

When xe11 in Formula 601 is two or more, two or more Ar₆₀₁(s) may belinked via a single bond.

In one or more embodiments, Ar₆₀₁ in Formula 601 may be an anthracenegroup.

In one or more embodiments, a compound represented by Formula 601 may berepresented by Formula 601-1:

In Formula 601-1,

X₆₁₄ may be N or C(R₆₁₄), X₆₁₅ may be N or C(R₆₁₅), X₆₁₆ may be N orC(R₆₁₆), and at least one selected from X₆₁₄ to X₆₁₆ may be N,

descriptions of L₆₁₁ to L₆₁₃ may each independently be the same as thatprovided in connection with L₆₀₁,

descriptions of xe611 to xe613 may each independently be the same asthat provided in connection with xe1,

descriptions of R₆₁₁ to R₆₁₃ may each independently be the same as thatprovided in connection with R₆₀₁, and

R₆₁₄ to R₆₁₆ may each independently be selected from hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group.

In one embodiment, L₆₀₁ and L₆₁₁ to L₆₁₃ in Formulae 601 and 601-1 mayeach independently be selected from:

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazolylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group; and

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazolylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, anaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group,an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenylgroup, a hexacenyl group, a pentacenyl group, a thiophenyl group, afuranyl group, a carbazolyl group, an indolyl group, an isoindolylgroup, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranylgroup, a dibenzothiophenyl group, a benzocarbazolyl group, adibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, anoxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, a triazinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, aphenanthridinyl group, an acridinyl group, a phenanthrolinyl group, aphenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, abenzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinylgroup, and an azacarbazolyl group;

but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, xe1 and xe611 to xe613 in Formulae 601 and601-1 may each independently be 0, 1, or 2.

In one or more embodiments, in Formulae 601 and 601-1, R₆₀₁ and R₆₁₁ toR₆₁₃ may each independently be selected from:

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group;

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, aperylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a thiophenyl group, a furanyl group, a carbazolyl group, anindolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group; and

—S(═O)₂(Q₆₀₁), and —P(═O)(Q₆₀₁)(Q₆₀₂), and

Q₆₀₁ and Q₆₀₂ are the same as described above.

The electron transport region may include at least one compound selectedfrom Compounds ET1 to ET36, but embodiments of the present disclosureare not limited thereto:

In one or more embodiments, the electron transport region may include atleast one compound selected from2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP),4,7-diphenyl-1,10-phenanthroline (Bphen), Alq₃, BAlq,3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole(TAZ), and NTAZ:

A thickness of the buffer layer, the hole blocking layer, and theelectron control layer may each independently be in a range of about 20Å to about 1,000 Å, for example, about 30 Å to about 300 Å. When thethicknesses of the buffer layer, the hole blocking layer, and theelectron control layer are within any of these ranges, the electrontransport region may have excellent (or suitable) hole blockingcharacteristics and/or electron control characteristics without asubstantial increase in driving voltage.

A thickness of the electron transport layer may be in a range of about100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. Whenthe thickness of the electron transport layer is within the rangedescribed above, the electron transport layer may have satisfactory (orsuitable) electron transport characteristics without a substantialincrease in driving voltage.

The electron transport region (e.g., the electron transport layer in theelectron transport region) may further include, in addition to thematerials described above, a metal-containing material.

The metal-containing material may include at least one selected fromalkali metal complex and alkaline earth-metal complex. The alkali metalcomplex may include a metal ion selected from a Li ion, a Na ion, a Kion, a Rb ion, and a Cs ion, and the alkaline earth-metal complex mayinclude a metal ion selected from a Be ion, a Mg ion, a Ca ion, a Srion, and a Ba ion. A ligand coordinated with the metal ion of the alkalimetal complex or the alkaline earth-metal complex may be selected from ahydroxy quinoline, a hydroxy isoquinoline, a hydroxy benzoquinoline, ahydroxy acridine, a hydroxy phenanthridine, a hydroxy phenyloxazole, ahydroxy phenylthiazole, a hydroxy diphenyloxadiazole, a hydroxydiphenylthiadiazole, a hydroxy phenylpyridine, a hydroxyphenylbenzimidazole, a hydroxy phenylbenzothiazole, a bipyridine, aphenanthroline, and a cyclopentadiene, but embodiments of the presentdisclosure are not limited thereto.

For example, the metal-containing material may include a Li complex. TheLi complex may include, for example, Compound ET-D1 (lithium quinolate,LiQ) and/or Compound ET-D2:

The electron transport region may include an electron injection layerthat facilitates injection of electrons from the second electrode 190.The electron injection layer may directly contact the second electrode190.

The electron injection layer may have i) a single-layered structureincluding a single layer including a single material, ii) asingle-layered structure including a single layer including a pluralityof different materials, or iii) a multi-layered structure having aplurality of layers including a plurality of different materials.

The electron injection layer may include an alkali metal, an alkalineearth metal, a rare earth metal, an alkali metal compound, an alkalineearth-metal compound, a rare earth metal compound, an alkali metalcomplex, an alkaline earth-metal complex, a rare earth metal complex, orany combination thereof.

The alkali metal may be selected from Li, Na, K, Rb, and Cs. In oneembodiment, the alkali metal may be Li, Na, or Cs. In one or moreembodiments, the alkali metal may be Li or Cs, but embodiments of thepresent disclosure are not limited thereto.

The alkaline earth metal may be selected from Mg, Ca, Sr, and Ba.

The rare earth metal may be selected from Sc, Y, Ce, Tb, Yb, and Gd.

The alkali metal compound, the alkaline earth-metal compound, and therare earth metal compound may each independently be selected from oxidesand halides (e.g., fluorides, chlorides, bromides, and/or iodides) ofthe alkali metal, the alkaline earth-metal, and the rare earth metal,respectively.

The alkali metal compound may be selected from alkali metal oxides (suchas Li₂O, Cs₂O, and/or K₂O) and alkali metal halides (such as LiF, NaF,CsF, KF, LiI, NaI, CsI, KI, and/or RbI). In one embodiment, the alkalimetal compound may be selected from LiF, Li₂O, NaF, LiI, NaI, CsI, andKI, but embodiments of the present disclosure are not limited thereto.

The alkaline earth-metal compound may be selected from alkalineearth-metal oxides, such as BaO, SrO, CaO, Ba_(x)Sr_(1-x)O (0<x<1),and/or Ba_(x)Ca_(1-x)O (0<x<1). In one embodiment, the alkalineearth-metal compound may be selected from BaO, SrO, and CaO, butembodiments of the present disclosure are not limited thereto.

The rare earth metal compound may be selected from YbF₃, ScF₃, ScO₃,Y₂O₃, Ce₂O₃, GdF₃, and TbF₃. In one embodiment, the rare earth metalcompound may be selected from YbF3, ScF₃, TbF₃, YbI₃, ScI₃, and TbI₃,but embodiments of the present disclosure are not limited thereto.

The alkali metal complex, the alkaline earth-metal complex, and the rareearth metal complex may include an ion of alkali metal, alkalineearth-metal, and rare earth metal as described above, respectively, anda ligand coordinated with a metal ion of the alkali metal complex, thealkaline earth-metal complex, or the rare earth metal complex may beselected from hydroxy quinoline, hydroxy isoquinoline, hydroxybenzoquinoline, hydroxy acridine, hydroxy phenanthridine, hydroxyphenyloxazole, hydroxy phenylthiazole, hydroxy diphenyloxadiazole,hydroxy diphenylthiadiazole, hydroxy phenylpyridine, hydroxyphenylbenzimidazole, hydroxy phenylbenzothiazole, bipyridine,phenanthroline, and cyclopentadiene, but embodiments of the presentdisclosure are not limited thereto.

The electron injection layer may include (e.g., consist of) an alkalimetal, an alkaline earth metal, a rare earth metal, an alkali metalcompound, an alkaline earth-metal compound, a rare earth metal compound,an alkali metal complex, an alkaline earth-metal complex, a rare earthmetal complex, or any combination thereof, as described above. In one ormore embodiments, the electron injection layer may further include anorganic material. When the electron injection layer further includes anorganic material, an alkali metal, an alkaline earth metal, a rare earthmetal, an alkali metal compound, an alkaline earth-metal compound, arare earth metal compound, an alkali metal complex, an alkalineearth-metal complex, a rare earth metal complex, or any combinationthereof may be homogeneously or non-homogeneously dispersed in a matrixincluding the organic material.

A thickness of the electron injection layer may be in a range of about 1Å to about 100 Å, for example, about 3 Å to about 90 Å. When thethickness of the electron injection layer is within the range describedabove, the electron injection layer may have satisfactory (or suitable)electron injection characteristics without a substantial increase indriving voltage.

The second electrode 190 may be disposed on the organic layer 150 havingthe structure according to embodiments of the present disclosure. Thesecond electrode 190 may be a cathode, which is an electron injectionelectrode, and in this regard, a material for forming the secondelectrode 190 may be selected from metal, an alloy, an electricallyconductive compound, and combinations thereof, which have a relativelylow work function.

The second electrode 190 may include at least one selected from lithium(Li), silver (Ag), magnesium (Mg), aluminum (Al), aluminum-lithium(Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver(Mg—Ag), ITO, and IZO, but embodiments of the present disclosure are notlimited thereto. The second electrode 190 may be a transmissiveelectrode, a semi-transmissive electrode, or a reflective electrode.

The first electrode 190 may have a single-layered structure, or amulti-layered structure including two or more layers.

Hereinbefore, the organic light-emitting device has been described withreference to the FIGURE, but embodiments of the present disclosure arenot limited thereto.

Layers constituting the hole transport region, the emission layer, andlayers constituting the electron transport region may each independentlybe formed in the respective region by using one or more suitable methodsselected from vacuum deposition, spin coating, casting,Langmuir-Blodgett (LB) deposition, ink-jet printing, laser-printing, andlaser-induced thermal imaging.

In one embodiment, the first organic layer is formed by performing asolution process, and the second organic layer is formed by deposition.

When any of the layers constituting the hole transport region, theemission layer, and the layers constituting the electron transportregion are formed by vacuum deposition, for example, the vacuumdeposition may be performed at a deposition temperature of about 100° C.to about 500° C., at a vacuum degree of about 10⁻⁸ torr to about 10⁻³torr, and at a deposition rate of about 0 Å/sec to about 100 Å/sec bytaking into account a material to be included in the layer to be formed,and the structure of the layer to be formed.

When any of the layers constituting the hole transport region, theemission layer, and the layers constituting the electron transportregion are formed by spin coating, the spin coating may be performed ata coating speed of about 2,000 rpm to about 5,000 rpm and at a heattreatment temperature of about 80° C. to about 200° C. by taking intoaccount a material to be included in the layer to be formed, and thestructure of the layer to be formed.

The term “C₁-C₆₀ alkyl group” as used herein may refer to a linear orbranched aliphatic saturated hydrocarbon monovalent group having 1 to 60carbon atoms, and non-limiting examples thereof include a methyl group,an ethyl group, a propyl group, an isobutyl group, a sec-butyl group, atert-butyl group, a pentyl group, an iso-amyl group, and a hexyl group.The term “C₁-C₆₀ alkylene group” as used herein may refer to a divalentgroup having the same structure as the C₁-C₆₀ alkyl group.

The term “C₂-C₆₀ alkenyl group” as used herein may refer to ahydrocarbon group having at least one carbon-carbon double bond in themiddle or at either terminus of the C₂-C₆₀ alkyl group, and non-limitingexamples thereof include an ethenyl group, a propenyl group, and abutenyl group. The term “C₂-C₆₀ alkenylene group” as used herein mayrefer to a divalent group having the same structure as the C₂-C₆₀alkenyl group.

The term “C₂-C₆₀ alkynyl group” as used herein may refer to ahydrocarbon group having at least one carbon-carbon triple bond in themiddle or at either terminus of the C₂-C₆₀ alkyl group, and non-limitingexamples thereof include an ethynyl group and a propynyl group. The term“C₂-C₆₀ alkynylene group” as used herein may refer to a divalent grouphaving the same structure as the C₂-C₆₀ alkynyl group.

The term “C₁-C₆₀ alkoxy group” as used herein may refer to a monovalentgroup represented by —OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl group),and non-limiting examples thereof include a methoxy group, an ethoxygroup, and an isopropoxy group.

The term “C₃-C₁₀ cycloalkyl group” as used herein may refer to amonovalent saturated hydrocarbon monocyclic group having 3 to 10 carbonatoms, and non-limiting examples thereof include a cyclopropyl group, acyclobutyl group, a cyclopentyl group, a cyclohexyl group, and acycloheptyl group. The term “C₃-C₁₀ cycloalkylene group” as used hereinmay refer to a divalent group having the same structure as the C₃-C₁₀cycloalkyl group.

The term “C₁-C₁₀ heterocycloalkyl group” as used herein may refer to amonovalent monocyclic group having at least one heteroatom selected fromN, O, Si, P, and S as a ring-forming atom and 1 to 10 carbon atoms, andnon-limiting examples thereof include a 1,2,3,4-oxatriazolidinyl group,a tetrahydrofuranyl group, and a tetrahydrothiophenyl group. The term“C₁-C₁₀ heterocycloalkylene group” as used herein may refer to adivalent group having the same structure as the C₁-C₁₀ heterocycloalkylgroup.

The term “C₃-C₁₀ cycloalkenyl group” as used herein may refer to amonovalent monocyclic group that has 3 to 10 carbon atoms and at leastone carbon-carbon double bond in the ring thereof and no aromaticity,and non-limiting examples thereof include a cyclopentenyl group, acyclohexenyl group, and a cycloheptenyl group. The term “C₃-C₁₀cycloalkenylene group” as used herein may refer to a divalent grouphaving the same structure as the C₃-C₁₀ cycloalkenyl group.

The term “C₁-C₁₀ heterocycloalkenyl group” as used herein may refer to amonovalent monocyclic group that has at least one heteroatom selectedfrom N, O, Si, P, and S as a ring-forming atom, 1 to 10 carbon atoms,and at least one carbon-carbon double bond in its ring. Non-limitingexamples of the C₁-C₁₀ heterocycloalkenyl group include a4,5-dihydro-1,2,3,4-oxatriazolyl group, a 2,3-dihydrofuranyl group, anda 2,3-dihydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkenylenegroup” as used herein may refer to a divalent group having the samestructure as the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group” as used herein may refer to a monovalentgroup having a carbocyclic aromatic system having 6 to 60 carbon atoms,and a C₆-C₆₀ arylene group used herein may refer to a divalent grouphaving a carbocyclic aromatic system having 6 to 60 carbon atoms.Non-limiting examples of the C₆-C₆₀ aryl group include a phenyl group, anaphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenylgroup, and a chrysenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀arylene group each independently include two or more rings, therespective rings may be fused to each other.

The term “C₁-C₆₀ heteroaryl group” as used herein may refer to amonovalent group having a carbocyclic aromatic system that has at leastone heteroatom selected from N, O, Si, P, and S as a ring-forming atom,in addition to 1 to 60 carbon atoms. The term “C₁-C₆₀ heteroarylenegroup” as used herein may refer to a divalent group having a carbocyclicaromatic system that has at least one heteroatom selected from N, O, Si,P, and S as a ring-forming atom, in addition to 1 to 60 carbon atoms.Non-limiting examples of the C₁-C₆₀ heteroaryl group include a pyridinylgroup, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, atriazinyl group, a quinolinyl group, and an isoquinolinyl group. Whenthe C₁-C₆₀ heteroaryl group and the C₁-C₆₀ heteroarylene group eachindependently include two or more rings, the respective rings may becondensed (e.g., fused) with each other.

The term “C₆-C₆₀ aryloxy group” as used herein may refer to a grouprepresented by —OA₁₀₂ (wherein A₁₀₂ is the C₆-C₆₀ aryl group), and theterm “C₆-C₆₀ arylthio group” as used herein may refer to a grouprepresented by —SA₁₀₃ (wherein A₁₀₃ is the C₆-C₆₀ aryl group).

The term “monovalent non-aromatic condensed polycyclic group” as usedherein may refer to a monovalent group having two or more ringscondensed (fused) with each other, only carbon atoms as ring-formingatoms (e.g., 8 to 60 carbon atoms), and no aromaticity in its entiremolecular structure. A non-limiting example of the monovalentnon-aromatic condensed polycyclic group is a fluorenyl group. The term“divalent non-aromatic condensed polycyclic group,” used herein, mayrefer to a divalent group having the same structure as the monovalentnon-aromatic condensed polycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group” asused herein may refer to a monovalent group having two or more ringscondensed (fused) to each other, at least one heteroatom selected fromN, O, Si, P, and S, other than carbon atoms (e.g., 1 to 60 carbonatoms), as ring-forming atoms, and no aromaticity in its entiremolecular structure. A non-limiting example of the monovalentnon-aromatic condensed heteropolycyclic group is a carbazolyl group. Theterm “divalent non-aromatic condensed heteropolycyclic group” as usedherein may refer to a divalent group having the same structure as themonovalent non-aromatic condensed heteropolycyclic group.

The term “C₅-C₆₀ carbocyclic group” as used herein may refer to amonocyclic or polycyclic group having 5 to 60 carbon atoms in whichring-forming atoms are carbon atoms only. The C₅-C₆₀ carbocyclic groupmay be an aromatic carbocyclic group or a non-aromatic carbocyclicgroup. The C₅-C₆₀ carbocyclic group may be a ring, such as benzene, amonovalent group, such as a phenyl group, or a divalent group, such as aphenylene group. In one or more embodiments, depending on the number ofsubstituents connected to the C₅-C₆₀ carbocyclic group, the C₅-C₆₀carbocyclic group may be a trivalent group or a quadrivalent group.

The term “C₁-C₆₀ heterocyclic group” as used herein may refer to a grouphaving the same structure as the C₁-C₆₀ carbocyclic group, except thatas a ring-forming atom, at least one heteroatom selected from N, O, Si,P, and S is used in addition to carbon atoms (the number of carbon atomsmay be in a range of 1 to 60).

At least one substituent of the substituted C₅-C₆₀ carbocyclic group,the substituted C₁-C₆₀ heterocyclic group, the substituted C₃-C₁₀cycloalkylene group, the substituted C₁-C₁₀ heterocycloalkylene group,the substituted C₃-C₁₀ cycloalkenylene group, the substituted C₁-C₁₀heterocycloalkenylene group, the substituted C₆-C₆₀ arylene group, thesubstituted C₁-C₆₀ heteroarylene group, the substituted divalentnon-aromatic condensed polycyclic group, the substituted divalentnon-aromatic condensed heteropolycyclic group, the substituted C₁-C₆₀alkyl group, the substituted C₂-C₆₀ alkenyl group, the substitutedC₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxy group, thesubstituted C₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, thesubstituted C₁-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ arylgroup, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀arylthio group, the substituted C₁-C₆₀ heteroaryl group, the substitutedmonovalent non-aromatic condensed polycyclic group, and the substitutedmonovalent non-aromatic condensed heteropolycyclic group may be selectedfrom:

deuterium (-D), —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, anda C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group,—Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁),—S(═O)₂(Q₁₁), and —P(═O)(Q₁₁)(Q₁₂);

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃),—N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and—P(═O)(Q₂₁)(Q₂₂); and —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),—C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂).

In one embodiment, at least one substituent of the substituted C₅-C₆₀carbocyclic group, the substituted C₁-C₆₀ heterocyclic group, thesubstituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group,the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxygroup, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, thesubstituted C₁-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ arylgroup, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀arylthio group, the substituted C₁-C₆₀ heteroaryl group, the substitutedmonovalent non-aromatic condensed polycyclic group, and the substitutedmonovalent non-aromatic condensed heteropolycyclic group may be selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, aC₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, a biphenyl group, and a terphenylgroup.

Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ may each independently beselected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, aC₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroarylgroup, a monovalent non-aromatic condensed polycyclic group, amonovalent non-aromatic condensed heteropolycyclic group, a biphenylgroup, and a terphenyl group.

In one embodiment, Q₃₁ to Q₃₃ may each independently be selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₆₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkylgroup, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl group substituted with aC₁-C₆₀ alkyl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromaticcondensed polycyclic group, a monovalent non-aromatic condensedheteropolycyclic group, a biphenyl group, and a terphenyl group.

In one embodiment, Q₃₁ to Q₃₃ may each independently be selected fromhydrogen, deuterium, a C₁-C₆₀ alkyl group, a C₃-C₁₀ cycloalkyl group, aC₆-C₆₀ aryl group, a C₆-C₆₀ aryl group substituted with a C₁-C₆₀ alkylgroup, and a C₁-C₆₀ heteroaryl group.

The term “Ph” as used herein may refer to a phenyl group, the term “Me”as used herein may refer to a methyl group, the term “Et” as used hereinmay refer to an ethyl group, the term “ter-Bu” or “Bu^(t),” as usedherein, may refer to a tert-butyl group, the term “OMe” as used hereinmay refer to a methoxy group, the term “TMS” as used herein may refer toa trimethylsilyl group, and “D” may refer to deuterium.

The term “biphenyl group” used herein may refer to a phenyl groupsubstituted with a phenyl group. For example, the “biphenyl group” maybe described as a “substituted phenyl group” having a “C₆-C₆₀ arylgroup” as a substituent.

The term “terphenyl group” used herein may refer to a phenyl groupsubstituted with a biphenyl group. For example, the “terphenyl group”may be described as a “phenyl group” having, as a substituent, a “C₆-C₆₀aryl group substituted with a C₆-C₆₀ aryl group.”

* and *′ used herein, unless defined otherwise, each refer to a bindingsite to a neighboring atom in a corresponding formula.

Hereinafter, a compound according to embodiments of the presentdisclosure and an organic light-emitting device including the same willbe described in more detail with reference to Synthesis Examples andExamples. The expression “B was used instead of A” used in describingSynthesis Examples and Examples may refer to an identical number ofmolar equivalents of A being used in place of molar equivalents of B.

SYNTHESIS EXAMPLES Synthesis Example 1: Synthesis of Compound 2

1) Synthesis of Intermediate 2-1

9H-thioxanthen-9-one was reacted with phenylmagnesium bromide to obtainIntermediate 2-1. Intermediate 2-1 was identified by LiquidChromatography-Mass Spectrometry (LC-MS).

C₁₉H₁₄OS: M+1 291.1.

2) Synthesis of Intermediate 2-2

Intermediate 2-1 and 9,9-dimethyl-10-phenyl-9,10-dihydroacridine (CAS#=717880-39-2) were reacted in the presence of Eaton's reagent to obtainIntermediate 2-2. Intermediate 2-2 was identified by LC-MS.

C₄₀H₃₁NS: M+1 558.3.

3) Synthesis of Compound 2

4.2 g of Intermediate 2-2 was dissolved in 30 mL of methylene chloride(MC), and 3.9 g of mCPBA was slowly added thereto. After 5 hours, anorganic layer was extracted from the reaction mixture by using MC andwashed with water. Then, the organic layer was dried by using magnesiumsulfate, and a solvent was evaporated therefrom. Then, the residueobtained therefrom was separated and purified by silica gel columnchromatography to obtain 2.3 g (yield: 51%) of Compound 2. Compound 2was identified by LC-MS and ¹H-NMR.

C₄₀H₃₁NS: M+1 558.3.

Synthesis Example 2: Synthesis of Compound 29

1) Synthesis of Intermediate 29-1

5H-cyclopenta[2,1-b:3,4-b′]dipyridine-5-one and phenylmagnesium bromidewere reacted to obtain Intermediate 29-1. Intermediate 29-1 wasidentified by LC-MS.

C₁₇H₁₂N₂O: M+1 261.2.

2) Synthesis of Compound 29

3.8 g of Intermediate 29-1 and 6.2 g of9,9-dimethyl-10-phenyl-9,10-dihydroacridine were dissolved in 50 mL ofMC, and 1 mL of Eaton's reagent was slowly added thereto. After stirringthe reaction mixture overnight, an organic layer was extracted from thereaction mixture by using MC and washed with water. Then, an organiclayer obtained therefrom was dried by using magnesium sulfate, and asolvent was evaporated therefrom. Then, the residue obtained therefromwas separated and purified by silica gel column chromatography to obtain3.2 g (yield: 41%) of Compound 29. Compound 29 was identified by LC-MSand ¹H-NMR.

Synthesis Example 3: Synthesis of Compound 41

Synthesis of Compound 41

4.5 g of Intermediate 2-2 was dissolved in 50 mL of MC, and 2 g of mCPBAwas slowly added thereto. After 1 hour, an organic layer was extractedfrom the reaction mixture by using MC and washed with water. Then, theorganic layer was dried by using magnesium sulfate, and a solvent wasevaporated therefrom. Then, the residue obtained therefrom was separatedand purified by silica gel column chromatography to obtain 3.6 g (yield:78%) of Compound 41. Compound 41 was identified by LC-MS and ¹H-NMR.

Synthesis Example 4: Synthesis of Compound 49

3.3 g of 10-hydroxy-10-phenylanthracene-9(10H)-one (CAS #=5146-30-5) and4.6 g of 9,9-dimethyl-10-phenyl-9,10-dihydroacridine were dissolved in50 mL of MC, and 1 mL of Eaton's reagent was slowly added dropwisethereto. After 1 hour, an organic layer was extracted from the reactionmixture by using MC and washed with water. Then, the organic layer wasdried by using magnesium sulfate, and a solvent was evaporatedtherefrom. Then, the residue obtained therefrom was separated andpurified by silica gel column chromatography to obtain 3.8 g (yield:64%) of Compound 49. Compound 49 was identified by LC-MS and ¹H-NMR.

Synthesis Example 5: Synthesis of Compound 63

1) Synthesis of Intermediate 63-1

2-chloro-9H-thioxanthen-9-one (CAS #=86-39-5) and phenylmagnesiumbromide were reacted to obtain Intermediate 63-1. Intermediate 63-1 wasidentified by LC-MS.

C₁₉H₁₃ClOS: M+1 325.3.

2) Synthesis of Intermediate 63-2

Intermediate 63-1 and 9,9-dimethyl-10-phenyl-9,10-dihydroacridine werereacted in the presence of Eaton's reagent to obtain Intermediate 63-2.Intermediate 63-2 was identified by LC-MS.

C₄₀H₃₀ClNS: M+1 592.5.

3) Synthesis of Intermediate 63-3

Intermediate 63-2 was oxidized by using mCPBA to obtain Intermediate63-3. Intermediate 63-3 was identified by LC-MS.

C₄₀H₃₀ClO₂NS: M+1 624.3.

4) Synthesis of Compound 63

6.1 g of Intermediate 63-3, 0.36 g of Pd₂dba₃, 0.37 g of XPhos, 2 g ofpotassium ferrocyanide hydrate, 1.9 g of potassium acetate, 25 mL of1,4-dioxane, and 25 mL of distilled water were added to a reactionvessel and stirred overnight. After the reaction was completed, anorganic layer was extracted from the reaction mixture by using ethylacetate and washed with distilled water. Then, the organic layer wasdried by using magnesium sulfate, and a solvent was evaporatedtherefrom. Then, the residue obtained therefrom was separated andpurified by silica gel column chromatography to obtain 2.9 g (yield:48%) of Compound 63. Compound 63 was identified by LC-MS and ¹H-NMR.

Synthesis Example 6: Synthesis of Compound 64

1) Synthesis of Intermediate 64-1

3-bromopyridine was reacted with n-BuLi and then reacted with5H-cyclopenta[2,1-b:3,4-b′]dipyridine-5-one to obtain Intermediate 64-1.Intermediate 64-1 was identified by LC-MS.

C₁₆H₁₁N₃O:M+1 262.1

2) Synthesis of Compound 64

2.8 g of Intermediate 64-1 and 4.6 g of9,9-dimethyl-10-phenyl-9,10-dihydroacridine were dissolved in 50 mL ofMC, and 1 mL of Eaton's reagent was slowly added dropwise thereto. After1 hour, an organic layer was extracted from the reaction mixture byusing MC and washed with water. Then, the organic layer was dried byusing magnesium sulfate, and a solvent was evaporated therefrom. Then,the residue obtained therefrom was separated and purified by silica gelcolumn chromatography to obtain 3.3 g (yield: 59%) of Compound 64.Compound 64 was identified by LC-MS and ¹H-NMR.

Synthesis Example 7: Synthesis of Compound 67

1) Synthesis of Intermediate 67-1

9H-thioxanthen-9-one was reacted with phenylmagnesium bromide to obtainIntermediate 67-1. Intermediate 67-1 was identified by LC-MS.

C₁₉H₁₄O₂: M+1 275.5.

2) Synthesis of Intermediate 67-2

9,9-dimethyl-9,10-dihydroacridine and 3-bromopyridine were reacted inthe presence of a Pd catalyst to obtain Intermediate 67-2. Intermediate67-2 was identified by LC-MS.

C₂₀H₁₈N₂: M+1 287.3.

3) Synthesis of Compound 67

2.1 g of Intermediate 67-1 and 3.3 g of Intermediate 67-2 were dissolvedin 40 mL of MC, and 0.5 mL of Eaton's reagent 0.5 mL was slowly addeddropwise thereto. After 4 hours, an organic layer was extracted from thereaction mixture by using MC and washed with water. Then, the organiclayer was dried by using magnesium sulfate, and a solvent was evaporatedtherefrom. Then, the residue obtained therefrom was separated andpurified by silica gel column chromatography to obtain 2.9 g (yield:72%) of Compound 67. Compound 67 was identified by LC-MS and ¹H-NMR.

Synthesis Example 8: Synthesis of Compound 71

1) Synthesis of Intermediate 71-1

9,9-dimethyl-9,10-dihydroacridine and 4-bromobenzonitrile were reactedin the presence of a Pd catalyst to obtain Intermediate 71-1.Intermediate 71-1 was identified by LC-MS.

C₂₂H₁₈N₂: M+1 311.7

2) Synthesis of Compound 71

1.7 g of Intermediate 2-1 and 2.7 g of Intermediate 71-1 were dissolvedin 30 mL of MC, and 0.3 mL of Eaton's reagent was slowly added dropwisethereto. After 4 hours, an organic layer was extracted from the reactionmixture by using MC and washed with water. Then, the organic layer wasdried by using magnesium sulfate, and a solvent was evaporatedtherefrom. Then, the residue obtained therefrom was separated andpurified by silica gel column chromatography to obtain 1.9 g (yield:55%) of Compound 71. Compound 71 was identified by LC-MS and ¹H-NMR.

¹H NMR and Mass Spectrometry/Fast Atom Bombardment (MS/FAB) results ofCompounds synthesized according to Synthesis Examples 1 to 8 are shownin Table 1 below. Synthesis methods of compounds other than Compoundsshown in Table 1 should be readily apparent to those of ordinary skillin the art by referring to the synthesis mechanisms and source materialsdescribed above.

TABLE 1 MS/FAB Found Compound ¹H NMR (CDCl₃, 400 MHz) [M + 1] calc. 27.75 (d, 2H), 7.40-7.27 (m, 10H), 7.17-6.98 590.32 589.21 (m, 12H), 6.76(t, 1H), 1.65 (s, 6H) 29 8.38 (d, 2H), 7.45 (d, 1H), 7.22-6.99 (m, 16H),528.33 527.24 6.79 (t, 2H), 6.74 (t, 1H), 1.66 (s, 6H) 41 7.49-7.42 (m,6H), 7.38 (d, 2H), 7.22-6.89 574.45 573.21 (m, 16H), 6.74 (t, 1H), 1.65(s, 6H) 42 8.33 (d, 2H), 7.49-7.40 (m, 4H), 7.22-7.15 (m, 11H), 554.10553.24 7.10-6.94 (m, 7H), 6.74 (t, 1H), 1.71 (s, 6H) 63 7.93 (d, 1H),7.84 (s, 1H), 7.74 (d, 1H), 7.65 (d, 1H), 615.39 614.20 7.39 (t, 1H),7.33 (d, 1H), 7.25-7.02 (m, 12H), 6.94 (t, 1H), 6.74 (t, 1H), 1.69 (s,6H) 64 8.41-8.35 (m, 4H), 7.67 (d, 1H), 7.48 (d, 2H), 7.22-6.97 529.65528.23 (m, 12H), 6.80 (t, 2H), 6.69 (t, 1H), 1.71 (s, 6H) 67 8.02 (s,1H), 7.93 (d, 1H), 7.3 (t, 1H), 7.22 (t, 2H), 543.89 542.24 7.11-6.95(m, 16H), 6.77 (d, 1H), 1.66 (s, 6H) 71 7.71 (d, 2H), 7.46 (m, 2H),7.33-7.00 (m, 16H), 583.11 582.21 6.92-6.90 (m, 3H), 6.72 (d, 1H), 1.66(s, 6H)

EXAMPLES Example 1

As an anode, a Corning 15 Ω/cm² (1,200 Å) ITO glass substrate was cut toa size of 50 mm×50 mm×0.7 mm, sonicated with isopropyl alcohol and purewater each for 5 minutes, and then cleaned by exposure to ultravioletrays and ozone for 30 minutes. Then, the resultant ITO glass substratewas provided to a vacuum deposition apparatus.

Compound NPD was vacuum-deposited on the ITO glass substrate to form ahole injection layer having a thickness of 300 Å, and mCP wasvacuum-deposited on the hole injection layer to form a hole transportlayer having a thickness of 200 Å. Compound 2 and Flrpic wereco-deposited on the hole transport layer at a weight ratio of 92:8 toform an emission layer having a thickness of 250 Å. Then, TAZ wasdeposited on the emission layer to form an electron transport layerhaving a thickness of 200 Å.

LiF, which is an alkali metal halide, was deposited on the electrontransport layer to form an electron injection layer having a thicknessof 10 Å, and Al was vacuum-deposited on the electron injection layer toform a cathode having a thickness of 100 Å, thereby forming a LiF/AIelectrode. In this manner, an organic light-emitting device wasmanufactured.

Examples 2 to 7 and Comparative Examples 1 to 4

Organic light-emitting devices were manufactured in the same (orsubstantially the same) manner as in Example 1, except that Compoundsshown in Table 2 were respectively used instead of Compound 2 in formingthe emission layer.

Example 8

As an anode, a Corning 15 Ω/cm² (1,200 Å) ITO glass substrate was cut toa size of 50 mm×50 mm×0.7 mm, sonicated with isopropyl alcohol and purewater each for 5 minutes, and then cleaned by exposure to ultravioletrays and ozone for 30 minutes. Then, the resultant ITO glass substratewas provided to a vacuum deposition apparatus.

Compound NPD was vacuum-deposited on the ITO glass substrate to form ahole injection layer having a thickness of 300 Å, and TCTA, which is ahole transport compound, was vacuum-deposited on the hole injectionlayer to form a hole transport layer having a thickness of 200 Å. CzSi,which is a hole transport layer compound, was vacuum-deposited on thehole transport layer to a thickness of 100 Å. Compound H101 and Compound2 were co-deposited on the hole transport layer at a weight ratio of90:10 to form an emission layer having a thickness of 200 Å. Then,Compound H101, as an electron transport layer compound, was deposited toa thickness of 200 Å, and TPBI, as an electron injection layer compound,was deposited to a thickness of 300 Å.

LiF, which is an alkali metal halide, was deposited on the electrontransport layer to form an electron injection layer having a thicknessof 10 Å, and Al was vacuum-deposited on the electron injection layer toform a cathode having a thickness of 3,000 Å, thereby forming a LiF/AIelectrode. In this manner, an organic light-emitting device wasmanufactured.

Examples 9 to 14 and Comparative Examples 5 to 8

Organic light-emitting devices were manufactured in the same (orsubstantially the same) manner as in Example 1, except that Compoundsshown in Table 3 were respectively used instead of Compound 2 in formingthe emission layer.

Evaluation Example

The driving voltage, efficiency, and color purity of the organiclight-emitting devices manufactured according to Examples 1 to 14 andComparative Examples 1 to 8 were measured by using the followingmethods, and results thereof are shown in Tables 2 and 3.

-   -   Color coordinates: A current-voltage meter (Keithley SMU 236)        supplied power and a luminance meter PR650 was used to measure        color coordinates.    -   Luminance: A current-voltage meter (Keithley SMU 236) supplied        power and a luminance meter PR650 was used to measure luminance.    -   Efficiency: A current-voltage meter (Keithley SMU 236) supplied        power and a luminance meter PR650 was used to measure        efficiency.

TABLE 2 Maximum Driving Current quantum voltage density efficiencyEmission Emission layer (V) (mA/cm²) (%) color Example 1 Compound 2 4.12.65 23.1 Blue Example 2 Compound 29 3.5 2.65 22.3 Blue Example 3Compound 41 3.3 2.65 19.9 Blue Example 4 Compound 49 3.7 2.65 21.0 BlueExample 5 Compound 63 3.8 2.65 22.1 Blue Example 6 Compound 64 3.9 2.6520.1 Blue Example 7 Compound 67 4.1 2.65 19.2 Blue Comparative BCPO 4.92.65 16.5 Blue Example 1 Comparative Comparative 4.5 2.65 12.2 BlueExample 2 Compound A Comparative Comparative 4.8 2.65 17.7 Blue Example3 Compound B Comparative Comparative 4.7 2.65 16.6 Blue Example 4Compound C

TABLE 3 Maximum Driving Current quantum voltage density efficiencyEmission Emission layer (V) (mA/cm²) (%) color Example 8 Compound 2 5.91 23.8 Blue Example 9 Compound 29 7.1 1 23.1 Blue Example 10 Compound 416.7 1 22.4 Blue Example 11 Compound 49 6.6 1 24.1 Blue Example 12Compound 63 6.9 1 20.5 Blue Example 13 Compound 64 6.0 1 21.1 BlueExample 14 Compound 67 6.8 1 21.5 Blue Comparative DPS 7.4 1 18.2 BlueExample 5 Comparative Comparative 6.5 1 11.5 Blue Example 6 Compound AComparative Comparative 7.1 1 12.4 Blue Example 7 Compound B ComparativeComparative 7.2 1 10.5 Blue Example 8 Compound C

Referring to Tables 2 and 3, it can be seen that the organiclight-emitting devices of the Examples manufactured by using theheterocyclic compound represented by Formula 1 (e.g., as a dopant or ahost) have excellent characteristics, as compared with those of theorganic light-emitting devices of the Comparative Examples.

In particular, the organic light-emitting devices of the Examples have alow driving voltage and excellent maximum quantum efficiency.

An organic light-emitting device including the heterocyclic compound mayhave a low driving voltage, high efficiency, high luminance, and a longlifespan.

As used herein, the terms “use,” “using,” and “used” may be consideredsynonymous with the terms “utilize,” “utilizing,” and “utilized,”respectively.

In addition, the terms “substantially,” “about,” and similar terms areused as terms of approximation and not as terms of degree, and areintended to account for the inherent deviations in measured orcalculated values that would be recognized by those of ordinary skill inthe art.

Also, any numerical range recited herein is intended to include allsubranges of the same numerical precision subsumed within the recitedrange. For example, a range of “1.0 to 10.0” is intended to include allsubranges between (and including) the recited minimum value of 1.0 andthe recited maximum value of 10.0, that is, having a minimum value equalto or greater than 1.0 and a maximum value equal to or less than 10.0,such as, for example, 2.4 to 7.6. Any maximum numerical limitationrecited herein is intended to include all lower numerical limitationssubsumed therein and any minimum numerical limitation recited in thisspecification is intended to include all higher numerical limitationssubsumed therein. Accordingly, Applicant reserves the right to amendthis specification, including the claims, to expressly recite anysub-range subsumed within the ranges expressly recited herein.

It should be understood that embodiments described herein should beconsidered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

While one or more embodiments have been described with reference to theFIGURES, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope of the present disclosure as definedby the following claims and equivalents thereof.

What is claimed is:
 1. A heterocyclic compound represented by Formula 1:

wherein, in Formulae 1 and 2, X₁ to X₈ are each independently selectedfrom N, CR₂, and CAr₁, provided that at least one of X₁ to X₈ is CAr₁,X₁₁ to X₁₈ are each independently N or CR₃, Y₁ is selected from O, S,NR₁₁, CR₁₂R₁₃, SiR₁₄R₁₅, CO, SO, SO₂, and POR₁₆, and Y₂ is selected froma single bond, O, S, NR₁₁, CR₁₂R₁₃, SiR₁₄R₁₅, CO, SO, SO₂, and POR₁₆; orY₁ is a single bond, and Y₂ is selected from O, S, CR₁₂R₁₃, SiR₁₄R₁₅,CO, SO, SO₂, and POR₁₆, when one of X₁ to X₈ is CAr₁ and Y₁ is a singlebond, Y₂ is selected from O, S, CR₁₂R₁₃, SiR₁₄R₁₅, CO, SO, SO₂, andPOR₁₆, Ar₁ is represented by Formula 2, L₁ is a substituted orunsubstituted C₅-C₆₀ carbocyclic group or a substituted or unsubstitutedC₁-C₆₀ heterocyclic group, R₁ to R₃ are each independently selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, —Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a substituted orunsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, asubstituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, and a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group,two or more neighboring R₂(s) are optionally linked to form asubstituted or unsubstituted ring, two or more neighboring R₃(s) areoptionally linked to form a substituted or unsubstituted ring, R₄ isselected from a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, and asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, R₁₁ to R₁₆ are each independently selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, —Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a substituted orunsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, asubstituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, and a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group,and neighboring substituents selected from R₁₁ to R₁₆ are optionallylinked to form a substituted or unsubstituted ring, provided that whenY₂ is CR₁₂R₁₃, R₁₂ and R₁₃ are not both an unsubstituted C₁-C₆₀ alkylgroup at the same time, a1 is an integer from 0 to 5, b1 is an integerfrom 1 to 5, at least one substituent of the substituted C₅-C₆₀carbocyclic group, the substituted C₁-C₆₀ heterocyclic group, thesubstituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group,the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxygroup, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, thesubstituted C₁-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ arylgroup, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀arylthio group, the substituted C₁-C₆₀ heteroaryl group, the substitutedmonovalent non-aromatic condensed polycyclic group, and the substitutedmonovalent non-aromatic condensed heteropolycyclic group is selectedfrom: deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, anda C₂-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted withat least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, a biphenyl group, and a terphenylgroup; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, aC₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group, a biphenylgroup, and a terphenyl group, each substituted with at least oneselected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amidino group, a hydrazino group, a hydrazonogroup, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, a biphenyl group, and a terphenylgroup; and —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), Q₃₁ to Q₃₃ are each independentlyselected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, aC₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl groupsubstituted with a C₁-C₆₀ alkyl group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, a biphenyl group, and aterphenyl group, and * indicates a binding site to a neighboring atom.2. The heterocyclic compound of claim 1, wherein X₃ or X₆ is CAr₁. 3.The heterocyclic compound of claim 1, wherein the heterocyclic compoundof Formula 1 is selected from Formulae 1-1 to 1-10:

wherein, in Formulae 1-1 to 1-10, definition for Ar₂ is the same as thatprovided in connection with Ar₁.
 4. The heterocyclic compound of claim1, wherein L₁ is selected from: a benzene group, a naphthalene group, afluorene group, a spiro-bifluorene group, a benzofluorene group, anaphthofluorene group, a pyridine group, a pyrimidine group, apyridazine group, a triazine group, a pyrrole group, a thiophene group,a furan group, an imidazole group, a pyrazole group, an oxazole group,an isoxazole group, a thiazole group, an isoxazole group, a triazolegroup, a carbazole group, a dibenzofuran group, a benzonaphthofurangroup, a dibenzothiophene group, a benzocarbazole group, and adibenzocarbazole group; and a benzene group, a naphthalene group, afluorene group, a spiro-bifluorene group, a benzofluorene group, anaphthofluorene group, a pyridine group, a pyrimidine group, apyridazine group, a triazine group, a pyrrole group, a thiophene group,a furan group, an imidazole group, a pyrazole group, an oxazole group,an isoxazole group, a thiazole group, an isoxazole group, a triazolegroup, a carbazole group, a dibenzofuran group, a benzonaphthofurangroup, a dibenzothiophene group, a benzocarbazole group, and adibenzocarbazole group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a methylgroup, an ethyl group, a propyl group, an isobutyl group, a sec-butylgroup, a ter-butyl group, a pentyl group, an iso-amyl group, a hexylgroup, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, acycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenylgroup, a naphthyl group, a fluorenyl group, a carbazolyl group, adibenzofuranyl group, a benzonaphthofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, and a dibenzocarbazolyl group.
 5. Theheterocyclic compound of claim 1, wherein R₁ to R₃ are eachindependently selected from: hydrogen, deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, —Si(Q₃₁)(Q₃₂)(Q₃₃),P(═O)(Q₃₁)(Q₃₂), a methyl group, an ethyl group, a propyl group, anisobutyl group, a sec-butyl group, a ter-butyl group, a pentyl group, aniso-amyl group, a hexyl group, and a C₁-C₂₀ alkoxy group; and—Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a methyl group, an ethyl group, apropyl group, an isobutyl group, a sec-butyl group, a ter-butyl group, apentyl group, an iso-amyl group, and a hexyl group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a methyl group, an ethyl group, a propylgroup, an isobutyl group, a sec-butyl group, a ter-butyl group, a pentylgroup, an iso-amyl group, and a hexyl group, and Q₃₁ to Q₃₃ are eachindependently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₆-C₆₀ aryl group,a C₆-C₆₀ aryl group substituted with a C₁-C₆₀ alkyl group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group, a biphenylgroup, and a terphenyl group.
 6. The heterocyclic compound of claim 1,wherein L₁ is selected from: a benzene group, a naphthalene group, afluorene group, a spiro-bifluorene group, a benzofluorene group, anaphthofluorene group, a pyridine group, a pyrimidine group, apyridazine group, a triazine group, a pyrrole group, a thiophene group,a furan group, an imidazole group, a pyrazole group, an oxazole group,an isoxazole group, a thiazole group, an isoxazole group, a triazolegroup, a carbazole group, a dibenzofuran group, and a dibenzothiophenegroup; and a benzene group, a naphthalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a naphthofluorene group,a pyridine group, a pyrimidine group, a pyridazine group, a triazinegroup, a pyrrole group, a thiophene group, a furan group, an imidazolegroup, a pyrazole group, an oxazole group, an isoxazole group, athiazole group, an isoxazole group, a triazole group, a carbazole group,a dibenzofuran group, and a dibenzothiophene group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a methyl group, an ethyl group, a propylgroup, an isobutyl group, a sec-butyl group, a ter-butyl group, a pentylgroup, an iso-amyl group, a hexyl group, a C₁-C₂₀ alkoxy group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopentenyl group, a cyclohexenyl group, a phenyl group, and anaphthyl group, R₁ is selected from: hydrogen, deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, —Si(Q₃₁)(Q₃₂)(Q₃₃),P(═O)(Q₃₁)(Q₃₂), a methyl group, an ethyl group, a propyl group, anisobutyl group, a sec-butyl group, a ter-butyl group, a pentyl group, aniso-amyl group, a hexyl group, and a C₁-C₂₀ alkoxy group; and—Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a methyl group, an ethyl group, apropyl group, an isobutyl group, a sec-butyl group, a ter-butyl group, apentyl group, an iso-amyl group, and a hexyl group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a methyl group, an ethyl group, a propylgroup, an isobutyl group, a sec-butyl group, a ter-butyl group, a pentylgroup, an iso-amyl group, and a hexyl group, and Q₃₁ to Q₃₃ are eachindependently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₆-C₆₀ aryl group,a C₆-C₆₀ aryl group substituted with a C₁-C₆₀ alkyl group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group, a biphenylgroup, and a terphenyl group.
 7. The heterocyclic compound of claim 1,wherein R₄ is represented by Formula 3:

wherein, in Formula 3, X₂₁ to X₂₅ are each independently N or CR₃, and *indicates a binding site to a neighboring atom.
 8. The heterocycliccompound of claim 7, wherein none of X₂₁ to X₂₅ are N or one to three ofX₂₁ to X₂₅ are N.
 9. The heterocyclic compound of claim 1, wherein noneof X₁₁ to X₁₄ are N or one to three of X₁₁ to X₁₄ are N.
 10. Theheterocyclic compound of claim 1, wherein none of X₁₅ to X₁₈ are N orone to three of X₁₅ to X₁₈ are N.
 11. A heterocyclic compoundrepresented by Formula 1:

wherein, in Formulae 1 and 2, X₁ to X₈ are each independently selectedfrom N, CR₂, and CAr₁, provided that at least one of X₁ to X₈ is CAr₁,X₁₁ to X₁₈ are each independently N or CR₃, Y₁ and Y₂ are eachindependently selected from a single bond, O, S, NR₁₁ CR₁₂R₁₃, SiR₁₄R₁₅,CO, SO, SO₂, and POR₁₆, when one of X₁ to X₈ is CAr₁ and Y₁ is a singlebond, Y₂ is selected from O, S, CR₁₂R₁₃, SiR₁₄R₁₅, CO, SO, SO₂, andPOR₁₆, Ar₁ is represented by Formula 2, L₁ is a substituted orunsubstituted C₅-C₆₀ carbocyclic group or a substituted or unsubstitutedC₁-C₆₀ heterocyclic group, R₁ to R₃ are each independently selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, —Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a substituted orunsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, asubstituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, and a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group,two or more neighboring R₂(s) are optionally linked to form asubstituted or unsubstituted ring, two or more neighboring R₃(s) areoptionally linked to form a substituted or unsubstituted ring, R₄ isselected from a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, and asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, R₁₁ to R₁₆ are each independently selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, —Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a substituted orunsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, anda substituted or unsubstituted C₁-C₆₀ alkoxy group, or neighboringsubstituents in R₁₁ to R₁₆ are linked to form a substituted orunsubstituted cyclopentane, a substituted or unsubstituted cyclohexane,a substituted or unsubstituted benzene, or a substituted orunsubstituted fluorene, provided that when Y₂ is CR₁₂R₁₃, R₁₂ and R₁₃are not both an unsubstituted C₁-C₆₀ alkyl group at the same time, a1 isan integer from 0 to 5, b1 is an integer from 1 to 5, at least onesubstituent of the substituted C₅-C₆₀ carbocyclic group, the substitutedC₁-C₆₀ heterocyclic group, the substituted C₁-C₆₀ alkyl group, thesubstituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group,the substituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkylgroup, the substituted C₁-C₁₀ heterocycloalkyl group, the substitutedC₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenylgroup, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxygroup, the substituted C₆-C₆₀ arylthio group, the substituted C₁-C₆₀heteroaryl group, the substituted monovalent non-aromatic condensedpolycyclic group, and the substituted monovalent non-aromatic condensedheteropolycyclic group is selected from: deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, and a C₂-C₆₀ alkoxy group; aC₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, anda C₁-C₆₀ alkoxy group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, and a monovalentnon-aromatic condensed heteropolycyclic group; a C₃-C₁₀ cycloalkylgroup, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, aC₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxygroup, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, a biphenyl group, and a terphenylgroup; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, aC₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group, a biphenylgroup, and a terphenyl group, each substituted with at least oneselected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amidino group, a hydrazino group, a hydrazonogroup, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, a biphenyl group, and a terphenylgroup; and —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), Q₃₁ to Q₃₃ are each independentlyselected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, aC₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl groupsubstituted with a C₁-C₆₀ alkyl group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, a biphenyl group, and aterphenyl group, and * indicates a binding site to a neighboring atom.12. The heterocyclic compound of claim 1, wherein Formula 2 is selectedfrom Formulae 2-1 to 2-11 and 2-13 to 2-19:

wherein Formulae 2-1 to 2-11 and 2-13 to 2-19 are each independentlyunsubstituted or substituted with one or more R₃(s), when one or more ofFormulae 2-1 to 2-11 and 2-13 to 2-19 are substituted with two or moreR₃(s), the R₃(s) are identical to or different from each other, and whenFormula 2 is Formula 2-17, Y₁ is selected from O, S, NR₁₁, CR₁₂R₁₃,SiR₁₄R₁₅, CO, SO, SO₂, and POR₁₆.
 13. An organic light-emitting devicecomprising: a first electrode; a second electrode facing the firstelectrode; and an organic layer between the first electrode and thesecond electrode, the organic layer comprising an emission layer,wherein the organic layer comprises the heterocyclic compound of claim1, wherein the first electrode comprises indium tin oxide (ITO), indiumzinc oxide (IZO), tin oxide (SnO₂), zinc oxide (ZnO), magnesium (Mg),silver (Ag), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca),magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), or any combinationthereof, and the second electrode comprises lithium (Li), Ag, Mg, Al,Al—Li, Ca, Mg—In, Mg—Ag, ITO, IZO, or any combination thereof.
 14. Theorganic light-emitting device of claim 13, wherein the first electrodeis an anode, the second electrode is a cathode, the organic layerfurther comprises a hole transport region between the first electrodeand the emission layer, and an electron transport region between theemission layer and the second electrode, the hole transport regioncomprises at least one layer selected from a hole injection layer, ahole transport layer, a buffer layer, an emission auxiliary layer, andan electron blocking layer, and the electron transport region comprisesat least one layer selected from a hole blocking layer, an electrontransport layer, and an electron injection layer.
 15. The organiclight-emitting device of claim 14, wherein the emission layer comprisesthe heterocyclic compound.
 16. The organic light-emitting device ofclaim 15, wherein the heterocyclic compound comprised in the emissionlayer is a host, and the emission layer further comprises aphosphorescent dopant.
 17. An organic light-emitting device comprising:a first electrode; a second electrode facing the first electrode; and anorganic layer between the first electrode and the second electrode, theorganic layer comprising an emission layer, wherein the emission layercomprises a heterocyclic compound represented by Formula 1:

wherein, in Formulae 1 and 2, X₁ to X₈ are each independently selectedfrom N, CR₂, and CAr₁, provided that at least one of X₁ to X₈ is CAr₁,X₁₁ to X₁₈ are each independently N or CR₃, Y₁ and Y₂ are eachindependently selected from a single bond, O, S, NR₁₁, CR₁₂R₁₃,SiR₁₄R₁₅, CO, SO, SO₂, and POR₁₆, when one of X₁ to X₈ is CAr₁ and Y₁ isa single bond, Y₂ is selected from O, S, CR₁₂R₁₃, SiR₁₄R₁₅, CO, SO, SO₂,and POR₁₆, Ar₁ is represented by Formula 2, L₁ is a substituted orunsubstituted C₅-C₆₀ carbocyclic group or a substituted or unsubstitutedC₁-C₆₀ heterocyclic group, R₁ to R₃ are each independently selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, —Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a substituted orunsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, asubstituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, and a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group,two or more neighboring R₂(s) are optionally linked to form asubstituted or unsubstituted ring, two or more neighboring R₃(s) areoptionally linked to form a substituted or unsubstituted ring, R₄ isselected from a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, and asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, R₁₁ to R₁₆ are each independently selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, —Si(Q₃₁)(Q₃₂)(Q₃₃), P(═O)(Q₃₁)(Q₃₂), a substituted orunsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, asubstituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, and a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group,and neighboring substituents selected from R₁₁ to R₁₆ are optionallylinked to form a substituted or unsubstituted ring, a1 is an integerfrom 0 to 5, b1 is an integer from 1 to 5, at least one substituent ofthe substituted C₅-C₆₀ carbocyclic group, the substituted C₁-C₆₀heterocyclic group, the substituted C₁-C₆₀ alkyl group, the substitutedC₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group, thesubstituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkylgroup, the substituted C₁-C₁₀ heterocycloalkyl group, the substitutedC₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenylgroup, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxygroup, the substituted C₆-C₆₀ arylthio group, the substituted C₁-C₆₀heteroaryl group, the substituted monovalent non-aromatic condensedpolycyclic group, and the substituted monovalent non-aromatic condensedheteropolycyclic group is selected from: deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; aC₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, anda C₁-C₆₀ alkoxy group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, and a monovalentnon-aromatic condensed heteropolycyclic group; a C₃-C₁₀ cycloalkylgroup, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, aC₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxygroup, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, a biphenyl group, and a terphenylgroup; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, aC₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group, a biphenylgroup, and a terphenyl group, each substituted with at least oneselected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amidino group, a hydrazino group, a hydrazonogroup, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, a biphenyl group, and a terphenylgroup; and —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), Q₃₁ to Q₃₃ are each independentlyselected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, aC₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl groupsubstituted with a C₁-C₆₀ alkyl group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, a biphenyl group, and aterphenyl group, and * indicates a binding site to a neighboring atom,and the heterocyclic compound comprised in the emission layer is adelayed fluorescent dopant and satisfies Equation 1:|E _(D, S1) −E _(D, T1)|≤0.3 eV,  Equation 1 wherein, in Equation 1,E_(D,S1) is singlet energy (eV) of the delayed fluorescent dopant, andE_(D,T1) is triplet energy (eV) of the delayed fluorescent dopant. 18.The organic light-emitting device of claim 15, wherein the heterocycliccompound is a delayed fluorescent dopant, the emission layer furthercomprises a host, and the delayed fluorescent dopant and the hostsatisfy Equation 2 or Equation 3:|E _(H, HOMO) −E _(D, HOMO)|≤0.5 eV  Equation 2|E _(H, LUMO) −E _(D, LUMO)|≤0.5 eV,  Equation 3 wherein, in Equations 2and 3, E_(H, HOMO) is a highest occupied molecular orbital (HOMO) energylevel of the host, E_(D, HOMO) is a HOMO energy level of the dopant,E_(H, LUMO) is a lowest unoccupied molecular orbital (LUMO) energy levelof the host, and E_(D, LUMO) is a LUMO energy level of the dopant. 19.The organic light-emitting device of claim 18, wherein the host is oneof Compounds H101 to H106: